SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6c49857dd4c5cf1e75fe367397128acde4906dedad6cf1602da28b53a56e6665' 
  AND token = 'XXZM32lfO3eQVzestF/wO0iQ7DKOZ/zazBYk99q39RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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