SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c340ea82641f90c2a6608e438e2d31607ddd7ac459e76e1ed9afe128c7394bc' 
  AND token = 'VZg5Jm0y0cXRAwQRgCi0cHdq1BusKe/Dqyu5g0b8ucE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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