SELECT 
  cscart_product_review_prepared_data.product_id AS product_id, 
  cscart_product_review_prepared_data.average_rating AS average_rating, 
  cscart_product_review_prepared_data.reviews_count AS reviews_count 
FROM 
  cscart_product_review_prepared_data 
WHERE 
  cscart_product_review_prepared_data.product_id IN (
    9765, 6876, 70243, 9950, 9951, 35876, 
    67447, 9952, 10004, 31002, 32922, 34523, 
    35857, 67448, 69929, 69930, 69959, 
    69964
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "8.92"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "storefront_id"
      ],
      "key_length": "7",
      "rows_examined_per_scan": 18,
      "rows_produced_per_join": 18,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "7.12",
        "eval_cost": "1.80",
        "prefix_cost": "8.92",
        "data_read_per_join": "288"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`cscart_db`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`cscart_db`.`cscart_product_review_prepared_data`.`product_id` in (9765,6876,70243,9950,9951,35876,67447,9952,10004,31002,32922,34523,35857,67448,69929,69930,69959,69964)))"
    }
  }
}