SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fe19248d121d5790454569e6827bab3308039b795235f0cdc195d045660d32d2' 
  AND token = 'WxoDqD7eqsPPBYO+/mPNX/XwqShgK5Mqz8GR/nD5e3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}