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 = 7210 
WHERE 
  cscart_products_categories.product_id IN (
    99127, 99128, 99129, 99130, 99131, 99132, 
    99134, 99135, 99143, 99144, 99162, 
    99163, 99164, 99165, 99166, 99168, 
    99171, 99172, 99173, 99174, 99175, 
    99176, 99177, 99178, 99179, 99180, 
    99182, 99183, 99184, 99192
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "33.19"
    },
    "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": 58,
            "rows_produced_per_join": 58,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "6.08",
              "eval_cost": "5.80",
              "prefix_cost": "11.88",
              "data_read_per_join": "928"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99127,99128,99129,99130,99131,99132,99134,99135,99143,99144,99162,99163,99164,99165,99166,99168,99171,99172,99173,99174,99175,99176,99177,99178,99179,99180,99182,99183,99184,99192))"
          }
        },
        {
          "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": 2,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "14.50",
              "eval_cost": "0.29",
              "prefix_cost": "32.18",
              "data_read_per_join": "7K"
            },
            "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": 2,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.73",
              "eval_cost": "0.29",
              "prefix_cost": "33.20",
              "data_read_per_join": "46"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
99127 7258M
99128 7258M
99129 7345,7347,7259M
99130 7320,7260M
99131 7349,7261M
99132 7320,7260M
99134 7320,7260M
99135 7349,7261M
99143 7320,7260M
99144 7349,7261M
99162 7258M
99163 7345,7347,7259M
99164 7320,7260M
99165 7349,7261M
99166 7320,7260M
99168 7349,7261M
99171 7258M
99172 7345,7347,7259M
99173 7320,7260M
99174 7349,7261M
99175 7320,7260M
99176 7349,7261M
99177 7258M
99178 7345,7347,7259M
99179 7349,7261M
99180 7320,7260M
99182 7258M
99183 7258M
99184 7345,7347,7259M
99192 7320,7260M