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 (
    278, 280, 282, 247, 248, 241, 244, 245, 
    246, 240, 6, 66
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.56"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "ALL",
      "possible_keys": [
        "PRIMARY"
      ],
      "rows_examined_per_scan": 52,
      "rows_produced_per_join": 12,
      "filtered": "23.08",
      "cost_info": {
        "read_cost": "10.17",
        "eval_cost": "2.40",
        "prefix_cost": "12.57",
        "data_read_per_join": "192"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`atulecarter_atul_demo5`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`atulecarter_atul_demo5`.`cscart_product_review_prepared_data`.`product_id` in (278,280,282,247,248,241,244,245,246,240,6,66)))"
    }
  }
}