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 (
    5978, 2760, 758, 764, 1352, 1390, 2596, 
    2599, 1356, 2595, 1395, 2601, 2600, 
    2598, 1379, 5817, 2768, 5814, 1378, 
    2772, 5843, 5854, 3413, 5956, 5910, 
    3329, 3377, 2543, 5861, 5839, 5830, 
    5801, 5804, 5815, 5849, 5806, 5836, 
    3591, 3374, 5808, 5809, 3409, 6004, 
    5920, 5879, 3403, 5885, 5911
  ) 
GROUP BY 
  products_categories.product_id

Query time 0.00159

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "75.68"
    },
    "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": 137,
            "rows_produced_per_join": 137,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "14.03",
              "eval_cost": "13.70",
              "prefix_cost": "27.73",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`goimagine`.`products_categories`.`product_id` in (5978,2760,758,764,1352,1390,2596,2599,1356,2595,1395,2601,2600,2598,1379,5817,2768,5814,1378,2772,5843,5854,3413,5956,5910,3329,3377,2543,5861,5839,5830,5801,5804,5815,5849,5806,5836,3591,3374,5808,5809,3409,6004,5920,5879,3403,5885,5911))"
          }
        },
        {
          "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": 6,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "34.25",
              "eval_cost": "0.69",
              "prefix_cost": "75.68",
              "data_read_per_join": "17K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}