SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
WHERE 
  cscart_products_categories.product_id IN (
    21567, 51083, 22715, 51082, 51085, 51081, 
    51088, 51087, 22713, 51086, 51089, 
    51090, 51092, 51093, 22714, 51091, 
    51095, 51096, 51097, 51098, 51100, 
    51099, 22716, 51103, 22712, 51105, 
    51102, 51101, 51123, 51122, 51121, 
    92, 49, 51129, 51128, 51127, 51126, 
    51125, 48, 51155, 51154, 51153, 51152, 
    21, 51158, 51157, 51156, 53, 51160, 
    51159, 51176, 51174, 51173, 51172, 
    91, 105, 50989, 46, 51370, 51371, 51372, 
    51373, 51452, 51453, 51496
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00232

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "167.94"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "29.80"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 383,
            "rows_produced_per_join": 15,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "40.09",
              "eval_cost": "1.53",
              "prefix_cost": "41.62",
              "data_read_per_join": "81K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`test_uchur_k`.`cscart_categories`.`storefront_id` in (0,1)) and ((`test_uchur_k`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`test_uchur_k`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`test_uchur_k`.`cscart_categories`.`usergroup_ids`))) and (`test_uchur_k`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "test_uchur_k.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 18,
            "rows_produced_per_join": 29,
            "filtered": "10.81",
            "index_condition": "(`test_uchur_k`.`cscart_products_categories`.`product_id` in (21567,51083,22715,51082,51085,51081,51088,51087,22713,51086,51089,51090,51092,51093,22714,51091,51095,51096,51097,51098,51100,51099,22716,51103,22712,51105,51102,51101,51123,51122,51121,92,49,51129,51128,51127,51126,51125,48,51155,51154,51153,51152,21,51158,51157,51156,53,51160,51159,51176,51174,51173,51172,91,105,50989,46,51370,51371,51372,51373,51452,51453,51496))",
            "cost_info": {
              "read_cost": "68.94",
              "eval_cost": "2.98",
              "prefix_cost": "138.14",
              "data_read_per_join": "476"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}