### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
for (BulkItemResponse bulkItemResponse : bulkResponse.getItems()) {
                            if (bulkItemResponse.isFailed()) {
                                Throwable cause = bulkItemResponse.getFailure().getCause();
                                final String failedApiKeyId = bulkItemResponse.getFailure().getId();
                                traceLog("invalidate api key", failedApiKeyId, cause);
                                failedRequestResponses.add(new ElasticsearchException("Error invalidating api key", cause));
                            } else {
                                UpdateResponse updateResponse = bulkItemResponse.getResponse();
                                if (updateResponse.getResult() == DocWriteResponse.Result.UPDATED) {
                                    logger.debug("Invalidated api key for doc [{}]", updateResponse.getId());
                                    invalidated.add(updateResponse.getId());
                                } else if (updateResponse.getResult() == DocWriteResponse.Result.NOOP) {
                                    previouslyInvalidated.add(updateResponse.getId());
                                }
                            }
                        }
                        InvalidateApiKeyResponse result = new InvalidateApiKeyResponse(
                            invalidated,
                            previouslyInvalidated,
                            failedRequestResponses
                        );
                        clearCache(result, listener);
                    }, e -> {
                        Throwable cause = ExceptionsHelper.unwrapCause(e);
                        traceLog("invalidate api keys", cause);
                        listener.onFailure(e);
                    }),
                    client::bulk
                )
            );