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, 
  product_position_source.position AS position 
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') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 7212 
WHERE 
  cscart_products_categories.product_id IN (
    84770, 84783, 84792, 87538, 88418, 89787, 
    85664, 85684, 85696, 85708, 84765, 
    85660, 85721, 85738, 85748, 85758, 
    87449, 88494, 88446, 88463, 88479, 
    89020, 89785, 85718, 88167, 88215, 
    88192, 88204, 88400, 84769, 84782, 
    84791, 85663, 85683, 85695, 85707, 
    87448, 88492, 84764, 85659, 89019, 
    89104, 89112, 87504, 87520, 88444, 
    88462, 88478, 90831, 88191, 88203, 
    87536, 88399, 88493, 84768, 84781, 
    84790, 87503, 87519, 88442, 88459, 
    88476, 88521, 89838, 89890, 89962, 
    88445, 84763, 89103, 89111, 90830, 
    89786, 89836, 89888, 89960, 87535, 
    88398, 88491, 88443, 90816, 89018, 
    89784, 87616, 87624, 90815, 89102, 
    89110, 90829, 89017, 88547, 87620, 
    87622, 88543, 89016
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00283

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "160.40"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 282,
            "rows_produced_per_join": 282,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "28.56",
              "eval_cost": "28.20",
              "prefix_cost": "56.76",
              "data_read_per_join": "4K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (84770,84783,84792,87538,88418,89787,85664,85684,85696,85708,84765,85660,85721,85738,85748,85758,87449,88494,88446,88463,88479,89020,89785,85718,88167,88215,88192,88204,88400,84769,84782,84791,85663,85683,85695,85707,87448,88492,84764,85659,89019,89104,89112,87504,87520,88444,88462,88478,90831,88191,88203,87536,88399,88493,84768,84781,84790,87503,87519,88442,88459,88476,88521,89838,89890,89962,88445,84763,89103,89111,90830,89786,89836,89888,89960,87535,88398,88491,88443,90816,89018,89784,87616,87624,90815,89102,89110,90829,89017,88547,87620,87622,88543,89016))"
          }
        },
        {
          "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": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 14,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "70.50",
              "eval_cost": "1.41",
              "prefix_cost": "155.46",
              "data_read_per_join": "36K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`nuie_scalesta_net`.`cscart_categories`.`storefront_id` in (0,1)) and ((`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`))) and (`nuie_scalesta_net`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "nuie_scalesta_net.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 14,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "3.53",
              "eval_cost": "1.41",
              "prefix_cost": "160.40",
              "data_read_per_join": "225"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}