SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4f09fe5fcad958a7dc6181edaedc8932859fd624d961317ef91a86ab0740f056' 
  AND token = 'ypXCAwfJcFhW+CzwsEJ5IAXFMx9twQm7sLADeR9edLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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