SELECT 
  company_descriptions.*, 
  companies.*, 
  vendor_plan_descriptions.plan, 
  seo_names.name as seo_name, 
  seo_names.path as seo_path, 
  vendor_ga_tracking_code, 
  vendor_fb_tracking_code, 
  AVG(discussion_rating.rating_value) AS average_rating, 
  CONCAT(
    companies.company_id, 
    '_', 
    IF (
      discussion_rating.thread_id, discussion_rating.thread_id, 
      '0'
    )
  ) AS company_thread_ids 
FROM 
  companies AS companies 
  LEFT JOIN company_descriptions AS company_descriptions ON company_descriptions.company_id = companies.company_id 
  AND company_descriptions.lang_code = 'en' 
  LEFT JOIN vendor_plan_descriptions ON companies.plan_id = vendor_plan_descriptions.plan_id 
  AND vendor_plan_descriptions.lang_code = 'en' 
  LEFT JOIN seo_names ON seo_names.object_id = 39 
  AND seo_names.type = 'm' 
  AND seo_names.dispatch = '' 
  AND seo_names.lang_code = 'en' 
  LEFT JOIN discussion as discussionA ON discussionA.object_id = companies.company_id 
  AND discussionA.object_type = 'M' 
  LEFT JOIN discussion_posts ON discussion_posts.thread_id = discussionA.thread_id 
  AND discussion_posts.status = 'A' 
  LEFT JOIN discussion_rating ON discussionA.thread_id = discussion_rating.thread_id 
  AND discussion_rating.post_id = discussion_posts.post_id 
WHERE 
  companies.company_id = 39

Query time 0.00278

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.62"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "companies",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "company_id"
          ],
          "key_length": "4",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "14K"
          },
          "used_columns": [
            "company_id",
            "status",
            "company",
            "lang_code",
            "address",
            "city",
            "state",
            "country",
            "zipcode",
            "email",
            "phone",
            "url",
            "storefront",
            "secure_storefront",
            "entry_page",
            "redirect_customer",
            "countries_list",
            "timestamp",
            "shippings",
            "logos",
            "request_user_id",
            "request_account_name",
            "request_account_data",
            "plan_id",
            "stripe_connect_account_id",
            "identifier_facebook_pixel",
            "featured_products",
            "sd_ga_tracking_code",
            "paypal_commerce_platform_account_id",
            "tagline",
            "url_facebook",
            "url_instagram",
            "url_twitter",
            "url_pinterest",
            "announcement",
            "shippo_api_token",
            "shippo_carrier",
            "shippo_service_type",
            "vendor_ga_tracking_code",
            "vendor_fb_tracking_code",
            "custom_domain",
            "custom_domain_status",
            "taxjar_key",
            "taxjar_export_statuses",
            "taxjar_export_csv_data",
            "ag_hide_city",
            "updated_timestamp",
            "suspend_date",
            "grace_period_start",
            "last_time_suspended",
            "last_debt_notification_time",
            "tax_number",
            "stripe_connect_account_type",
            "registered_from_storefront_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "company_descriptions",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "company_id",
            "lang_code"
          ],
          "key_length": "10",
          "ref": [
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "company_id",
            "lang_code",
            "company_description",
            "terms",
            "subdomain_colors",
            "i18n_company",
            "i18n_address",
            "i18n_city"
          ]
        }
      },
      {
        "table": {
          "table_name": "vendor_plan_descriptions",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "plan_id",
            "lang_code"
          ],
          "key_length": "10",
          "ref": [
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "plan_id",
            "lang_code",
            "plan"
          ]
        }
      },
      {
        "table": {
          "table_name": "seo_names",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "dispatch"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "object_id",
            "type",
            "dispatch",
            "lang_code"
          ],
          "key_length": "206",
          "ref": [
            "const",
            "const",
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.84",
            "eval_cost": "0.10",
            "prefix_cost": "0.94",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "name",
            "object_id",
            "type",
            "dispatch",
            "path",
            "lang_code"
          ]
        }
      },
      {
        "table": {
          "table_name": "discussionA",
          "access_type": "const",
          "possible_keys": [
            "object_id"
          ],
          "key": "object_id",
          "used_key_parts": [
            "object_id",
            "object_type"
          ],
          "key_length": "6",
          "ref": [
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.67",
            "eval_cost": "0.10",
            "prefix_cost": "1.71",
            "data_read_per_join": "24"
          },
          "used_columns": [
            "thread_id",
            "object_id",
            "object_type"
          ]
        }
      },
      {
        "table": {
          "table_name": "discussion_posts",
          "access_type": "ref",
          "possible_keys": [
            "thread_id",
            "thread_id_2"
          ],
          "key": "thread_id_2",
          "used_key_parts": [
            "thread_id",
            "status"
          ],
          "key_length": "6",
          "ref": [
            "goimagine.discussionA.thread_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.18",
            "prefix_cost": "2.13",
            "data_read_per_join": "787"
          },
          "used_columns": [
            "post_id",
            "thread_id",
            "status"
          ]
        }
      },
      {
        "table": {
          "table_name": "discussion_rating",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "thread_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "post_id"
          ],
          "key_length": "3",
          "ref": [
            "goimagine.discussion_posts.post_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "1.32",
            "eval_cost": "0.18",
            "prefix_cost": "3.63",
            "data_read_per_join": "28"
          },
          "used_columns": [
            "rating_value",
            "post_id",
            "thread_id"
          ],
          "attached_condition": "<if>(is_not_null_compl(discussion_rating), (`goimagine`.`discussion_rating`.`thread_id` = `goimagine`.`discussionA`.`thread_id`), true)"
        }
      }
    ]
  }
}

Result

company_id lang_code company_description terms subdomain_colors i18n_company i18n_address i18n_city status company address city state country zipcode email phone url storefront secure_storefront entry_page redirect_customer countries_list timestamp shippings logos request_user_id request_account_name request_account_data plan_id stripe_connect_account_id identifier_facebook_pixel featured_products sd_ga_tracking_code paypal_commerce_platform_account_id tagline url_facebook url_instagram url_twitter url_pinterest announcement shippo_api_token shippo_carrier shippo_service_type vendor_ga_tracking_code vendor_fb_tracking_code custom_domain custom_domain_status taxjar_key taxjar_export_statuses taxjar_export_csv_data ag_hide_city updated_timestamp suspend_date grace_period_start last_time_suspended last_debt_notification_time tax_number stripe_connect_account_type registered_from_storefront_id plan seo_name seo_path average_rating company_thread_ids
39 en <div class="video-container"><iframe style="width: 500px; height: 281px;" src="//www.youtube.com/embed/MXrOUqMKBOI" frameborder="0" allowfullscreen=""></iframe></div> <p><strong>Welcome to My Shop!</strong></p> <p><span class="mt-xs-1" data-inplace-editable-text="story" data-endpoint="AboutPost" data-key="story" data-placeholder="How did you get started? What inspires you? We know each seller’s story is unique&mdash;tell yours here.">I hope I have surprised you by all the designs I have to offer. I believe there is a little something for everyone. If you don't find what you are looking for I do have a custom Light switch option. I can put your dog, girlfriend, child's Art Work, almost anything on a light switch. Just message me a good size JPG. Your light switch is only as good as your picture so make it a good one.</span></p> <p>Processing time:</p> <p>I need 5-7 Business Days to make this product, plus shipping time from USPS</p> <p><br></p> <p>returns and exchange Policy</p> <p><strong>I do not accept returns or exchanges</strong>.&nbsp;These products are handmade in your choice of Pattern and Switch Combinations.&nbsp; If you receive a broken product Please send me a photo and I will gladly send out a new one.&nbsp; I will of course replace any item that was shipped out wrong due to my error.</p> {"tmenu_style":"V","default_colors":"N","link_color":"#007d89","label_color":"#00a0af","icon_color":"#00a0af","main_btn_color":"#6dd1d6","branded_text_color":"#00a0af","vbp_1_url":"","vbp_2_url":"","vbp_3_url":"","vba_1_url":"","vba_2_url":"","vba_3_url":""} Switch Cover Supply PO Box 22 Keene A Switch Cover Supply PO Box 22 Keene CA US 93531 angela.quinn314@gmail.com none Y 1584394914 0 a:4:{s:14:"company_fields";a:2:{i:37;s:6:"Angela";i:38;s:5:"Quinn";}s:15:"admin_firstname";s:6:"Angela";s:14:"admin_lastname";s:5:"Quinn";s:6:"fields";a:0:{}} 9 acct_1GNSxwGp2Ngd7q68 141,152,299,3163 UA-176580648-1 Switch Up Your Switch Plates https://www.facebook.com/Switch-Cover-Supply-515572848900594 switch_cover_supply UA-176580648-1 A {"items_per_file":"2500","time_from":"","time_to":""} N 0 0 0 0 0 S All-Star Investor switchcoversupply 5.0000 39_844