SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    65703, 65684, 65705, 65704, 65686, 65701, 
    65698, 65700, 65691, 65685, 65688, 
    65694, 65696, 65702, 65697, 65695, 
    65690, 65689, 65693, 65692
  )

Query time 0.00088

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": 20,
      "filtered": 100,
      "attached_condition": "cscart_products.product_id in (65703,65684,65705,65704,65686,65701,65698,65700,65691,65685,65688,65694,65696,65702,65697,65695,65690,65689,65693,65692)"
    }
  }
}

Result