### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
}
    }
    private void buildResponseAndClearCache(
        final BulkResponse bulkResponse,
        final BulkUpdateApiKeyResponse.Builder responseBuilder,
        final ActionListener<BulkUpdateApiKeyResponse> listener
    ) {
        for (BulkItemResponse bulkItemResponse : bulkResponse.getItems()) {
            final String apiKeyId = bulkItemResponse.getId();
            if (bulkItemResponse.isFailed()) {
                responseBuilder.error(
                    apiKeyId,
                    new ElasticsearchException("bulk request execution failure", bulkItemResponse.getFailure().getCause())
                );
            } else {
                
                assert bulkItemResponse.getResponse().getResult() == DocWriteResponse.Result.UPDATED;
                responseBuilder.updated(apiKeyId);
            }
        }
        clearApiKeyDocCache(responseBuilder.build(), listener);
    }
    private static void addLimitedByRoleDescriptors(final XContentBuilder builder, final Set<RoleDescriptor> limitedByRoleDescriptors)
        throws IOException {
        assert limitedByRoleDescriptors != null;
        builder.startObject("limited_by_role_descriptors");
        for (RoleDescriptor descriptor : limitedByRoleDescriptors) {
            builder.field(descriptor.getName(), (contentBuilder, params) -> descriptor.toXContent(contentBuilder, params, true));
        }
        builder.endObject();