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 = 7345 
WHERE 
  cscart_products_categories.product_id IN (
    88066, 88075, 88082, 87958, 89982, 89983, 
    89984, 88046, 88045, 87987, 87997, 
    88026, 88047, 88048, 88050, 88051, 
    87937, 87950, 87952, 88004, 87948, 
    88029, 93794, 94496, 94499, 94501, 
    94515, 94581, 94843, 94850, 94852, 
    95309, 95316, 95376, 95762, 95778, 
    95779, 95823, 96119, 96508, 96530, 
    96570, 96572, 97620, 97623, 97625, 
    97639, 97705, 99111, 99122, 99124, 
    99126, 99129, 99163, 99172, 99178, 
    99184, 99204, 99207, 99223, 99224, 
    99225, 99226, 99228, 99229, 99244, 
    99253, 99260, 99271, 99280, 99281, 
    100388, 100389, 100432, 100671, 100672, 
    100673
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01302

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "133.88"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "8.98"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 208,
            "rows_produced_per_join": 8,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "20.72",
              "eval_cost": "0.83",
              "prefix_cost": "21.55",
              "data_read_per_join": "21K"
            },
            "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": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 117,
            "rows_produced_per_join": 8,
            "filtered": "0.92",
            "cost_info": {
              "read_cost": "2.33",
              "eval_cost": "0.90",
              "prefix_cost": "121.75",
              "data_read_per_join": "143"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (88066,88075,88082,87958,89982,89983,89984,88046,88045,87987,87997,88026,88047,88048,88050,88051,87937,87950,87952,88004,87948,88029,93794,94496,94499,94501,94515,94581,94843,94850,94852,95309,95316,95376,95762,95778,95779,95823,96119,96508,96530,96570,96572,97620,97623,97625,97639,97705,99111,99122,99124,99126,99129,99163,99172,99178,99184,99204,99207,99223,99224,99225,99226,99228,99229,99244,99253,99260,99271,99280,99281,100388,100389,100432,100671,100672,100673))"
          }
        },
        {
          "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": 8,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.25",
              "eval_cost": "0.90",
              "prefix_cost": "124.90",
              "data_read_per_join": "143"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}