### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
.filter(QueryBuilders.termQuery("doc_type", "api_key"))
                .filter(QueryBuilders.termQuery("type", ApiKey.Type.CROSS_CLUSTER.value()));
            findApiKeys(boolQuery, true, true, this::convertSearchHitToApiKeyInfo, ActionListener.wrap(apiKeyInfos -> {
                int ccsKeys = 0, ccrKeys = 0, ccsCcrKeys = 0;
                for (ApiKey apiKeyInfo : apiKeyInfos) {
                    assert apiKeyInfo.getType() == ApiKey.Type.CROSS_CLUSTER;
                    assert apiKeyInfo.getRoleDescriptors().size() == 1;
                    final String[] clusterPrivileges = apiKeyInfo.getRoleDescriptors().iterator().next().getClusterPrivileges();
                    if (Arrays.equals(clusterPrivileges, CCS_CLUSTER_PRIVILEGE_NAMES)) {
                        ccsKeys += 1;
                    } else if (Arrays.equals(clusterPrivileges, CCR_CLUSTER_PRIVILEGE_NAMES)) {
                        ccrKeys += 1;
                    } else if (Arrays.equals(clusterPrivileges, CCS_AND_CCR_CLUSTER_PRIVILEGE_NAMES)) {
                        ccsCcrKeys += 1;
                    } else {
                        final String message = "invalid cluster privileges ["
                            + Strings.arrayToCommaDelimitedString(clusterPrivileges)
                            + "] for cross-cluster API key ["
                            + apiKeyInfo.getId()
                            + "]";
                        assert false : message;
                        listener.onFailure(new IllegalStateException(message));
                    }
                }
                listener.onResponse(Map.of("total", apiKeyInfos.size(), "ccs", ccsKeys, "ccr", ccrKeys, "ccs_ccr", ccsCcrKeys));
            }, listener::onFailure));
        }
    }
    
    public static final class ApiKeyCredentials implements AuthenticationToken, Closeable {