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 (
    2467, 2468, 2469, 2470, 2471, 2472, 2473, 
    2475, 2476, 2477, 2478, 2483, 2482, 
    2484, 2485, 2486, 2487, 2488, 2489, 
    2490, 2491, 2492, 2493, 2494, 2495, 
    2496, 2497, 2499, 2500, 2503, 2504, 
    2505, 2517, 2518, 2519, 2524, 2525, 
    2526, 2527, 2528, 2529, 2530, 2531, 
    2538, 2540, 2541, 2550, 2549, 2548, 
    2544, 2551, 2552, 2534, 2564, 2565, 
    2576, 2577, 2578, 2579, 2580, 2581, 
    2585, 2586, 2596, 2597, 2598, 2599, 
    2600, 2601, 2602, 2604, 2605, 2606, 
    2607, 2608, 2615, 2620, 2621, 2623, 
    2624, 2625, 2626, 2631, 2632, 2633, 
    2685, 2686, 2687, 2502, 3639, 8417, 
    8418, 8419, 8420, 8398, 8415, 8416, 
    8421, 8399, 8476, 8477, 10140, 10141, 
    10142, 10143, 10144, 10145, 10224, 
    10223, 10222, 10228, 10229, 10230, 
    10233, 10234
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00420

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "231.96"
    },
    "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": 254,
            "rows_produced_per_join": 254,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (2467,2468,2469,2470,2471,2472,2473,2475,2476,2477,2478,2483,2482,2484,2485,2486,2487,2488,2489,2490,2491,2492,2493,2494,2495,2496,2497,2499,2500,2503,2504,2505,2517,2518,2519,2524,2525,2526,2527,2528,2529,2530,2531,2538,2540,2541,2550,2549,2548,2544,2551,2552,2534,2564,2565,2576,2577,2578,2579,2580,2581,2585,2586,2596,2597,2598,2599,2600,2601,2602,2604,2605,2606,2607,2608,2615,2620,2621,2623,2624,2625,2626,2631,2632,2633,2685,2686,2687,2502,3639,8417,8418,8419,8420,8398,8415,8416,8421,8399,8476,8477,10140,10141,10142,10143,10144,10145,10224,10223,10222,10228,10229,10230,10233,10234))",
            "cost_info": {
              "read_cost": "117.66",
              "eval_cost": "25.40",
              "prefix_cost": "143.06",
              "data_read_per_join": "3K"
            },
            "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": 12,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "63.50",
              "eval_cost": "1.27",
              "prefix_cost": "231.96",
              "data_read_per_join": "39K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}