SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '87c7c74519bbdf63128ec03e77fbab28f90eefbd2e17edb44526e34d931bf0c7' 
  AND token = 'WRUm6qL3qwaCMTaB/x1LaXQpZe2gKUYSh9tkuOfgIPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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