SELECT 
  video_id, 
  product_id 
FROM 
  q_ab__video_gallery 
WHERE 
  product_id IN (
    6121, 6122, 6123, 6124, 6125, 6126, 6127, 
    6128, 6129, 6130, 6131, 6132, 6133, 
    6134, 6135, 6136
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "7.42"
    },
    "table": {
      "table_name": "q_ab__video_gallery",
      "access_type": "range",
      "possible_keys": [
        "product_id"
      ],
      "key": "product_id",
      "used_key_parts": [
        "product_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 16,
      "rows_produced_per_join": 16,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "4.22",
        "eval_cost": "3.20",
        "prefix_cost": "7.42",
        "data_read_per_join": "1K"
      },
      "used_columns": [
        "video_id",
        "product_id"
      ],
      "attached_condition": "(`portal`.`q_ab__video_gallery`.`product_id` in (6121,6122,6123,6124,6125,6126,6127,6128,6129,6130,6131,6132,6133,6134,6135,6136))"
    }
  }
}