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 (
    13439, 13440, 13441, 13442, 13443, 13444, 
    13445, 13446, 13447, 13448, 13449, 
    13450, 13451, 13452, 13453, 13454, 
    13455, 13456, 13457, 13458, 13459, 
    13460, 13461, 13462, 13467, 13468, 
    13469, 13470, 13471, 13472, 13473, 
    13474, 13475, 13476, 13477, 13478, 
    13479, 13480, 13481, 13482, 13483, 
    13484, 13485, 13486, 13487, 13488, 
    13489, 13490
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00085

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.126210922,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products_categories",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "pt"],
          "key": "pt",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 48,
          "cost": 0.04915296,
          "filtered": 100,
          "attached_condition": "cscart_products_categories.product_id in (13439,13440,13441,13442,13443,13444,13445,13446,13447,13448,13449,13450,13451,13452,13453,13454,13455,13456,13457,13458,13459,13460,13461,13462,13467,13468,13469,13470,13471,13472,13473,13474,13475,13476,13477,13478,13479,13480,13481,13482,13483,13484,13485,13486,13487,13488,13489,13490)",
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["category_id"],
          "ref": ["u508912950_dev_2025.cscart_products_categories.category_id"],
          "loops": 48,
          "rows": 1,
          "cost": 0.04620992,
          "filtered": 100,
          "attached_condition": "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')"
        }
      }
    ]
  }
}