SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a59b2612d97447972721c652165f942419deb74319725ced5ffc4d53c2af2a3' 
  AND token = 'UMtrTIZBcqhkSsJt7MVIoQOGu6KX9FgyN1zibA61Gfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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