### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
if (bulkRequestBuilder.numberOfActions() == 0) {
            logger.trace("No bulk request execution necessary for API key update");
            listener.onResponse(responseBuilder.build());
            return;
        }
        logger.trace("Executing bulk request to update [{}] API keys", bulkRequestBuilder.numberOfActions());
        bulkRequestBuilder.setRefreshPolicy(RefreshPolicy.WAIT_UNTIL);
        securityIndex.prepareIndexIfNeededThenExecute(
            ex -> listener.onFailure(traceLog("prepare security index before update", ex)),
            () -> executeAsyncWithOrigin(
                client.threadPool().getThreadContext(),
                SECURITY_ORIGIN,
                bulkRequestBuilder.request(),
                ActionListener.<BulkResponse>wrap(
                    bulkResponse -> buildResponseAndClearCache(bulkResponse, responseBuilder, listener),
                    ex -> listener.onFailure(traceLog("execute bulk request for update", ex))
                ),
                client::bulk
            )
        );
    }
    
    void validateForUpdate(
        final String apiKeyId,
        final ApiKey.Type expectedType,
        final Authentication authentication,
        final ApiKeyDoc apiKeyDoc
    ) {
        assert authentication.getEffectiveSubject().getUser().principal().equals(apiKeyDoc.creator.get("principal"));
        if (apiKeyDoc.invalidated) {