SELECT 
  video.video_id 
FROM 
  cscart_cp_video_product_links as link 
  LEFT JOIN cscart_cp_videos as video ON link.video_id = video.video_id 
WHERE 
  link.product_id IN (36421) 
  AND link.type = 'T' 
ORDER BY 
  link.position

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.38"
    },
    "ordering_operation": {
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "link",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "4",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "10.00",
            "index_condition": "(`cscart_db`.`link`.`type` = 'T')",
            "cost_info": {
              "read_cost": "0.25",
              "eval_cost": "0.01",
              "prefix_cost": "0.35",
              "data_read_per_join": "2"
            },
            "used_columns": [
              "video_id",
              "product_id",
              "type",
              "position"
            ]
          }
        },
        {
          "table": {
            "table_name": "video",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "video_id_idx"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "video_id"
            ],
            "key_length": "3",
            "ref": [
              "cscart_db.link.video_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 0,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "0.03",
              "eval_cost": "0.01",
              "prefix_cost": "0.39",
              "data_read_per_join": "160"
            },
            "used_columns": [
              "video_id"
            ]
          }
        }
      ]
    }
  }
}