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 (
    3354, 3834, 3308, 3306, 3841, 3212, 3226, 
    3350, 3218, 3392, 3301, 3751, 3828, 
    3520, 3529, 3809, 3518, 3918, 3215, 
    3213, 3597, 3752, 3552, 3836, 3232, 
    3589, 3556, 3845, 3822, 3370, 3843, 
    3840, 3882, 3377, 3373, 3593, 3551, 
    3831, 3519, 3919, 3356, 3404, 3366, 
    3222, 3522, 3401, 3358, 3537, 3291, 
    3225, 3844, 3876, 3559, 3917, 3528, 
    3819, 3922, 3534, 3531, 3812, 3372, 
    3374, 3309, 3590, 3351, 3532, 3546, 
    3827, 3548, 3521, 3355, 3398, 3357, 
    3369, 3807, 3525, 3408, 3746, 3393, 
    3744
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00386

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "210.41"
    },
    "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": 238,
            "rows_produced_per_join": 238,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_products_categories`.`product_id` in (3354,3834,3308,3306,3841,3212,3226,3350,3218,3392,3301,3751,3828,3520,3529,3809,3518,3918,3215,3213,3597,3752,3552,3836,3232,3589,3556,3845,3822,3370,3843,3840,3882,3377,3373,3593,3551,3831,3519,3919,3356,3404,3366,3222,3522,3401,3358,3537,3291,3225,3844,3876,3559,3917,3528,3819,3922,3534,3531,3812,3372,3374,3309,3590,3351,3532,3546,3827,3548,3521,3355,3398,3357,3369,3807,3525,3408,3746,3393,3744))",
            "cost_info": {
              "read_cost": "103.31",
              "eval_cost": "23.80",
              "prefix_cost": "127.11",
              "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": 11,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "59.50",
              "eval_cost": "1.19",
              "prefix_cost": "210.41",
              "data_read_per_join": "37K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}