### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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/test/java/org/elasticsearch/xpack/security/authc/ApiKeyServiceTests.java
assertBusy(() -> assertThat(service.getEvictionCounter().longValue() >= 4500, is(true)));
            appender.addExpectation(
                new MockLogAppender.SeenEventExpectation(
                    "evict",
                    ApiKeyService.class.getName(),
                    Level.TRACE,
                    "API key with ID [*] was evicted from the authentication cache*"
                )
            );
            appender.addExpectation(
                new MockLogAppender.SeenEventExpectation(
                    "thrashing",
                    ApiKeyService.class.getName(),
                    Level.WARN,
                    "Possible thrashing for API key authentication cache,*"
                )
            );
            apiKeyAuthCache.put(randomAlphaOfLength(22), new ListenableFuture<>());
            appender.assertAllExpectationsMatched();
            
            assertThat(service.getLastEvictionCheckedAt().get(), lessThanOrEqualTo(System.nanoTime()));
            assertBusy(() -> assertThat(service.getEvictionCounter().longValue(), equalTo(0L)));
            
            appender.addExpectation(
                new MockLogAppender.SeenEventExpectation(
                    "evict-again",
                    ApiKeyService.class.getName(),
                    Level.TRACE,
                    "API key with ID [*] was evicted from the authentication cache*"
                )