### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
listener.onResponse(GetApiKeyResponse.emptyResponse());
                } else {
                    listener.onResponse(new GetApiKeyResponse(apiKeyInfos));
                }
            }, listener::onFailure)
        );
    }
    public void queryApiKeys(SearchRequest searchRequest, boolean withLimitedBy, ActionListener<QueryApiKeyResponse> listener) {
        ensureEnabled();
        final SecurityIndexManager frozenSecurityIndex = securityIndex.freeze();
        if (frozenSecurityIndex.indexExists() == false) {
            logger.debug("security index does not exist");
            listener.onResponse(QueryApiKeyResponse.emptyResponse());
        } else if (frozenSecurityIndex.isAvailable() == false) {
            listener.onFailure(frozenSecurityIndex.getUnavailableReason());
        } else {
            securityIndex.checkIndexVersionThenExecute(
                listener::onFailure,
                () -> executeAsyncWithOrigin(
                    client,
                    SECURITY_ORIGIN,
                    SearchAction.INSTANCE,
                    searchRequest,
                    ActionListener.wrap(searchResponse -> {
                        final long total = searchResponse.getHits().getTotalHits().value;
                        if (total == 0) {
                            logger.debug("No api keys found for query [{}]", searchRequest.source().query());
                            listener.onResponse(QueryApiKeyResponse.emptyResponse());
                            return;
                        }