SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9735304af649476383a8c75eb98fdcd3e425f1480dbdbdad753d124c5339afdc' 
  AND token = 'iaJsMw7Ywj5nya1812wfBnklNTfLhBglKNIQXnpTQTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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