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 (
    12714, 12715, 12716, 12717, 12718, 12719, 
    12720, 12721, 12722, 12723, 12724, 
    12725, 12726, 12727, 12728, 12729, 
    12730, 12731, 12732, 12733, 12734, 
    12735, 12736, 12737, 12738, 12739, 
    12740, 12741, 12742, 12743
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00093

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "53.56"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "6.26"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 46,
            "rows_produced_per_join": 1,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "5.15",
              "eval_cost": "0.18",
              "prefix_cost": "5.33",
              "data_read_per_join": "7K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`test2_gaseus`.`cscart_categories`.`storefront_id` in (0,1)) and ((`test2_gaseus`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`test2_gaseus`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`test2_gaseus`.`cscart_categories`.`usergroup_ids`))) and (`test2_gaseus`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 34,
            "rows_produced_per_join": 6,
            "filtered": "10.00",
            "index_condition": "(`test2_gaseus`.`cscart_products_categories`.`product_id` in (12714,12715,12716,12717,12718,12719,12720,12721,12722,12723,12724,12725,12726,12727,12728,12729,12730,12731,12732,12733,12734,12735,12736,12737,12738,12739,12740,12741,12742,12743))",
            "using_join_buffer": "hash join",
            "cost_info": {
              "read_cost": "35.71",
              "eval_cost": "0.63",
              "prefix_cost": "47.30",
              "data_read_per_join": "100"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`test2_gaseus`.`cscart_products_categories`.`category_id` = `test2_gaseus`.`cscart_categories`.`category_id`)"
          }
        }
      ]
    }
  }
}