SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 
    30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 
    40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 
    50
  )

Query time 0.00088

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rows": 32,
          "filtered": 100,
          "index_condition": "cscart_products.product_id in (19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50)"
        }
      }
    ]
  }
}