### Description

The [Get API key information API](https://www.elastic.co/guide/en/elasticsearch/reference/master/security-api-get-api-key.html) can currently filter the returned keys by:
 * key id/name
 * keys owned by the calling user
 * keys owned by other users, by `realm_name` and `username`

Irrespective of the filtering used, both invalidated and expired (but not yet deleted) keys will be included in the response.
In the response, keys have the `invalidated` boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.

I propose we introduce a way for the API to support retrieving:
* only valid API keys (not return invalidated keys) - using a boolean request parameter
* keys not expired before a certain timestamp - using a timestamp parameter that defaults to "now" - also note that keys' experiation date is always checked against the local node's clock
x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/rest/action/apikey/RestGetApiKeyAction.java
public final class RestGetApiKeyAction extends ApiKeyBaseRestHandler {
    public RestGetApiKeyAction(Settings settings, XPackLicenseState licenseState) {
        super(settings, licenseState);
    }
    @Override
    public List<Route> routes() {
        return List.of(new Route(GET, "/_security/api_key"));
    }
    @Override
    protected RestChannelConsumer innerPrepareRequest(RestRequest request, NodeClient client) throws IOException {
        final String apiKeyId = request.param("id");
        final String apiKeyName = request.param("name");