SELECT 
  products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      products_categories.link_type = "M", 
      CONCAT(
        products_categories.category_id, 
        "M"
      ), 
      products_categories.category_id
    )
  ) AS category_ids 
FROM 
  products_categories 
  INNER JOIN categories ON categories.category_id = products_categories.category_id 
  AND categories.storefront_id IN (0, 1) 
  AND (
    categories.usergroup_ids = '' 
    OR FIND_IN_SET(0, categories.usergroup_ids) 
    OR FIND_IN_SET(1, categories.usergroup_ids)
  ) 
  AND categories.status IN ('A', 'H') 
WHERE 
  products_categories.product_id IN (
    187599, 79185, 79358, 82647, 82677, 
    82659, 82664, 82650, 79359, 82662, 
    80067, 82658, 189127, 191122, 197476, 
    82675, 83702, 82663, 199702, 188170, 
    187601, 191601, 188620, 201635, 82665, 
    191770, 82674, 210711, 203577, 82670, 
    169289, 153234, 259182, 259310, 269097, 
    247890, 269118, 247892, 269100, 269096, 
    269091, 269090, 247902, 259643, 269113, 
    247897, 258388, 269098, 269093, 269116, 
    259598, 269111, 269107, 269108, 259655, 
    269094, 269095, 204373, 283319, 292893, 
    283328, 284130, 306484, 269110, 306494, 
    269106
  ) 
GROUP BY 
  products_categories.product_id

Query time 0.00274

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "135.11"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 245,
            "rows_produced_per_join": 245,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "24.86",
              "eval_cost": "24.50",
              "prefix_cost": "49.36",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`goimagine`.`products_categories`.`product_id` in (187599,79185,79358,82647,82677,82659,82664,82650,79359,82662,80067,82658,189127,191122,197476,82675,83702,82663,199702,188170,187601,191601,188620,201635,82665,191770,82674,210711,203577,82670,169289,153234,259182,259310,269097,247890,269118,247892,269100,269096,269091,269090,247902,259643,269113,247897,258388,269098,269093,269116,259598,269111,269107,269108,259655,269094,269095,204373,283319,292893,283328,284130,306484,269110,306494,269106))"
          }
        },
        {
          "table": {
            "table_name": "categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "goimagine.products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 12,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "61.25",
              "eval_cost": "1.23",
              "prefix_cost": "135.11",
              "data_read_per_join": "32K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`goimagine`.`categories`.`storefront_id` in (0,1)) and ((`goimagine`.`categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`goimagine`.`categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`goimagine`.`categories`.`usergroup_ids`))) and (`goimagine`.`categories`.`status` in ('A','H')))"
          }
        }
      ]
    }
  }
}