### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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/authc/ApiKeyService.java
realmsQuery.should(QueryBuilders.termQuery("creator.realm", realmName));
            }
            realmsQuery.minimumShouldMatch(1);
            return realmsQuery;
        }
    }
    private void findVersionedApiKeyDocsForSubject(
        final Authentication authentication,
        final String[] apiKeyIds,
        final ActionListener<Collection<VersionedApiKeyDoc>> listener
    ) {
        assert authentication.isApiKey() == false;
        findApiKeysForUserRealmApiKeyIdAndNameCombination(
            getOwnersRealmNames(authentication),
            authentication.getEffectiveSubject().getUser().principal(),
            null,
            apiKeyIds,
            false,
            false,
            ApiKeyService::convertSearchHitToVersionedApiKeyDoc,
            listener
        );
    }
    private <T> void findApiKeysForUserRealmApiKeyIdAndNameCombination(
        String[] realmNames,
        String userName,
        String apiKeyName,
        String[] apiKeyIds,
        boolean filterOutInvalidatedKeys,
        boolean filterOutExpiredKeys,