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 (
    2587, 2588, 2589, 2590, 2593, 2594, 2595, 
    2603, 2609, 2610, 2611, 2613, 2614, 
    2617, 2618, 2619, 2622, 2696, 2697, 
    2695, 2694, 2704, 2705, 2706, 2723, 
    2724, 2725, 2726, 2739, 2740, 2741, 
    2742, 2743, 2744, 2745, 2761, 2762, 
    2763, 2764, 2828, 2830, 2841, 2865, 
    2872, 2873, 2874, 2875, 3096, 3097, 
    3098, 3104, 3105, 3106, 3136, 3137, 
    3138, 3423, 3422, 3610, 3556, 3557, 
    3593, 3594, 3812, 3813, 3876, 3877, 
    4888, 4891, 4892, 5122, 5121, 5124, 
    5125, 5155, 5156, 5157, 5158, 6271, 
    6272, 10022, 10028
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00347

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "177.31"
    },
    "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": 196,
            "rows_produced_per_join": 196,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (2587,2588,2589,2590,2593,2594,2595,2603,2609,2610,2611,2613,2614,2617,2618,2619,2622,2696,2697,2695,2694,2704,2705,2706,2723,2724,2725,2726,2739,2740,2741,2742,2743,2744,2745,2761,2762,2763,2764,2828,2830,2841,2865,2872,2873,2874,2875,3096,3097,3098,3104,3105,3106,3136,3137,3138,3423,3422,3610,3556,3557,3593,3594,3812,3813,3876,3877,4888,4891,4892,5122,5121,5124,5125,5155,5156,5157,5158,6271,6272,10022,10028))",
            "cost_info": {
              "read_cost": "89.11",
              "eval_cost": "19.60",
              "prefix_cost": "108.71",
              "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": 9,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "49.00",
              "eval_cost": "0.98",
              "prefix_cost": "177.31",
              "data_read_per_join": "30K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}