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 (
    389822, 415384, 415526, 388396, 388725, 
    388794, 389025, 389273, 389056, 389538, 
    389564, 388897, 388812, 388821, 415715, 
    388501, 388859, 389489, 388753, 388827
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.87"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "ALL",
      "possible_keys": [
        "PRIMARY"
      ],
      "rows_examined_per_scan": 19,
      "rows_produced_per_join": 19,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "2.07",
        "eval_cost": "3.80",
        "prefix_cost": "5.87",
        "data_read_per_join": "304"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`webmarco`.`cscart_product_review_prepared_data`.`product_id` in (389822,415384,415526,388396,388725,388794,389025,389273,389056,389538,389564,388897,388812,388821,415715,388501,388859,389489,388753,388827)))"
    }
  }
}