SELECT 
  COUNT(DISTINCT cv.video_id) 
FROM 
  cscart_cp_videos cv 
  LEFT JOIN cscart_cp_video_descriptions cvd ON cvd.video_id = cv.video_id 
  AND cvd.lang_code = 'en' 
WHERE 
  1 
  AND cv.video_id IN (
    2415, 2414, 2413, 2318, 2248, 2252, 2311, 
    2304, 2163, 2162, 2161, 2155, 2131, 
    2130, 2129, 2128, 2082, 2081, 2080, 
    2079, 2078, 2077, 2076
  ) 
  AND cv.status = 'A'

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.51"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "cv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "status_idx",
            "video_id_idx",
            "idx_cp_videos_status_userid_videoid",
            "idx_status_timestamp"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "video_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 23,
          "rows_produced_per_join": 15,
          "filtered": "67.15",
          "index_condition": "(`cscart_db`.`cv`.`video_id` in (2415,2414,2413,2318,2248,2252,2311,2304,2163,2162,2161,2155,2131,2130,2129,2128,2082,2081,2080,2079,2078,2077,2076))",
          "cost_info": {
            "read_cost": "14.57",
            "eval_cost": "1.54",
            "prefix_cost": "16.11",
            "data_read_per_join": "24K"
          },
          "used_columns": [
            "video_id",
            "status"
          ],
          "attached_condition": "(`cscart_db`.`cv`.`status` = 'A')"
        }
      },
      {
        "table": {
          "table_name": "cvd",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "video_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "cscart_db.cv.video_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 15,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "3.86",
            "eval_cost": "1.54",
            "prefix_cost": "21.52",
            "data_read_per_join": "64K"
          },
          "used_columns": [
            "video_id",
            "lang_code"
          ]
        }
      }
    ]
  }
}

Result

COUNT(DISTINCT cv.video_id)
20