SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d9b0cedd80b6621c4a974e2c86ae564038cd72350291a3d7b7123078c8de798' 
  AND token = 'QHUI9oqJVLozHOdDcUHqqWy6H5oLAcYFF+pXz/n8BLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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