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 (
    51297, 51296, 139, 51300, 51299, 51298, 
    51304, 51303, 51302, 51301, 138, 51443, 
    51309, 51308, 51307, 51306, 51305, 
    129, 54, 51313, 51312, 51314, 51311, 
    51310, 51361, 30, 51362, 51363, 51364, 
    51365, 31, 51366, 51367, 51368, 51369, 
    46, 51370, 51371, 51372, 51373, 51452, 
    51453, 42, 51376, 51377, 51378, 51379, 
    51380, 88, 51395, 51396, 51397, 51555, 
    51556
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00201

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "164.82"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "26.69"
      },
      "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": 26,
            "filtered": "9.68",
            "index_condition": "(`test_uchur_k`.`cscart_products_categories`.`product_id` in (51297,51296,139,51300,51299,51298,51304,51303,51302,51301,138,51443,51309,51308,51307,51306,51305,129,54,51313,51312,51314,51311,51310,51361,30,51362,51363,51364,51365,31,51366,51367,51368,51369,46,51370,51371,51372,51373,51452,51453,42,51376,51377,51378,51379,51380,88,51395,51396,51397,51555,51556))",
            "cost_info": {
              "read_cost": "68.94",
              "eval_cost": "2.67",
              "prefix_cost": "138.14",
              "data_read_per_join": "426"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}