SELECT 
  tmall_product_review_prepared_data.product_id AS product_id, 
  tmall_product_review_prepared_data.average_rating AS average_rating, 
  tmall_product_review_prepared_data.reviews_count AS reviews_count 
FROM 
  tmall_product_review_prepared_data 
WHERE 
  tmall_product_review_prepared_data.product_id IN (248) 
  AND tmall_product_review_prepared_data.storefront_id = 0

Query time 0.00754

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "tmall_product_review_prepared_data",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "7",
          "used_key_parts": ["product_id", "storefront_id"],
          "ref": ["const", "const"],
          "rows": 1,
          "filtered": 100
        }
      }
    ]
  }
}