SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    7942, 7941, 7602, 7601, 7603, 7829, 7828, 
    7940, 8071, 8718, 7446, 8909, 8380, 
    7830, 7762
  )

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 15,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (7942,7941,7602,7601,7603,7829,7828,7940,8071,8718,7446,8909,8380,7830,7762)"
    }
  }
}