### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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/test/java/org/elasticsearch/xpack/security/authc/ApiKeyServiceTests.java
assertThat(ApiKeyService.getCreatorRealmName(authentication5), equalTo(authentication5.getEffectiveSubject().getRealm().getName()));
        assertThat(ApiKeyService.getCreatorRealmType(authentication5), equalTo(authentication5.getEffectiveSubject().getRealm().getType()));
        
        final Authentication authentication6 = authentication3.runAs(AuthenticationTests.randomUser(), null);
        assertThat(
            ApiKeyService.getCreatorRealmName(authentication6),
            equalTo(authentication6.getAuthenticatingSubject().getRealm().getName())
        );
        assertThat(
            ApiKeyService.getCreatorRealmType(authentication6),
            equalTo(authentication6.getAuthenticatingSubject().getRealm().getType())
        );
    }
    public void testGetOwnersRealmNames() {
        
        RealmRef realmRef = AuthenticationTests.randomRealmRef(false);
        Authentication authentication = Authentication.newRealmAuthentication(AuthenticationTests.randomUser(), realmRef);
        assertThat(Arrays.asList(ApiKeyService.getOwnersRealmNames(authentication)), contains(realmRef.getName()));
        assertThat(Arrays.asList(ApiKeyService.getOwnersRealmNames(authentication.token())), contains(realmRef.getName()));
        
        authentication = Authentication.newRealmAuthentication(
            AuthenticationTests.randomUser(),
            AuthenticationTests.randomRealmRef(randomBoolean())
        );
        assertThat(
            Arrays.asList(ApiKeyService.getOwnersRealmNames(authentication.runAs(AuthenticationTests.randomUser(), realmRef))),
            contains(realmRef.getName())
        );
        assertThat(
            Arrays.asList(ApiKeyService.getOwnersRealmNames(authentication.runAs(AuthenticationTests.randomUser(), realmRef).token())),