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 (
    39124, 66758, 65547, 39922, 69901, 67036, 
    65175, 65171
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.21"
    },
    "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": 8,
      "rows_produced_per_join": 8,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "4.41",
        "eval_cost": "0.80",
        "prefix_cost": "5.21",
        "data_read_per_join": "128"
      },
      "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 (39124,66758,65547,39922,69901,67036,65175,65171)))"
    }
  }
}