### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
assertEquals(1, apiKeyAuthCache.count());
            appender.assertAllExpectationsMatched();
        } finally {
            appender.stop();
            Loggers.setLevel(logger, Level.INFO);
            Loggers.removeAppender(logger, appender);
        }
    }
    public void testApiKeyAuthCacheWillLogWarningOnPossibleThrashing() throws Exception {
        ApiKeyService service = createApiKeyService(Settings.builder().put("xpack.security.authc.api_key.cache.max_keys", 2).build());
        final Cache<String, ListenableFuture<CachedApiKeyHashResult>> apiKeyAuthCache = service.getApiKeyAuthCache();
        
        apiKeyAuthCache.put(randomAlphaOfLength(20), new ListenableFuture<>());
        apiKeyAuthCache.put(randomAlphaOfLength(21), new ListenableFuture<>());
        final Logger logger = LogManager.getLogger(ApiKeyService.class);
        Loggers.setLevel(logger, Level.TRACE);
        final MockLogAppender appender = new MockLogAppender();
        Loggers.addAppender(logger, appender);
        appender.start();
        try {
            
            service.getEvictionCounter().add(4500);
            final long thrashingCheckIntervalInSeconds = 300L;
            final long secondsToNanoSeconds = 1_000_000_000L;
            
            
            
            final long lastCheckedAt = System.nanoTime() - (thrashingCheckIntervalInSeconds + 10L) * secondsToNanoSeconds;
            service.getLastEvictionCheckedAt().set(lastCheckedAt);