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 (
    8562, 8563, 8564, 8565, 8619, 8621, 8622, 
    8623, 8624, 8625, 8918, 8919, 8920, 
    8627, 8631, 8632, 8633, 8692, 8655, 
    8656, 8657, 8658, 8659, 8660, 8663, 
    8664, 8665, 8666, 8667, 8668, 8935, 
    8568, 8685, 8560, 8686, 8689, 8690, 
    8691, 8731, 8733, 8732, 8734, 8735, 
    8736, 8739, 8740, 8776, 8777, 8779, 
    8780, 8781, 8782, 8838, 8840, 8916, 
    8917, 8748, 8927, 8933, 8934, 8936, 
    8937, 8939, 8940, 8941, 8943
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00139

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "69.31"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "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": 66,
            "rows_produced_per_join": 66,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (8562,8563,8564,8565,8619,8621,8622,8623,8624,8625,8918,8919,8920,8627,8631,8632,8633,8692,8655,8656,8657,8658,8659,8660,8663,8664,8665,8666,8667,8668,8935,8568,8685,8560,8686,8689,8690,8691,8731,8733,8732,8734,8735,8736,8739,8740,8776,8777,8779,8780,8781,8782,8838,8840,8916,8917,8748,8927,8933,8934,8936,8937,8939,8940,8941,8943))",
            "cost_info": {
              "read_cost": "39.61",
              "eval_cost": "6.60",
              "prefix_cost": "46.21",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "softwarepirmam_hewadelivard_cscart_4.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 3,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "16.50",
              "eval_cost": "0.33",
              "prefix_cost": "69.31",
              "data_read_per_join": "10K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`storefront_id` in (0,1)) and ((`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`usergroup_ids`))) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_categories`.`status` in ('A','H')))"
          }
        }
      ]
    }
  }
}