### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
RoleDescriptor.parse("key-role", new BytesArray("{\"cluster\":[\"monitor\"]}"), true, XContentType.JSON)
        );
        final Map<String, Object> metadata3 = mockKeyDocument(
            docId3,
            apiKey3,
            new User("banner", "superuser"),
            null,
            false,
            Duration.ofSeconds(3600),
            keyRoles,
            type
        );
        PlainActionFuture<AuthenticationResult<User>> future3 = new PlainActionFuture<>();
        service.loadApiKeyAndValidateCredentials(threadContext, apiKeyCredentials3, future3);
        final ApiKeyService.CachedApiKeyDoc cachedApiKeyDoc3 = service.getDocCache().get(docId3);
        assertNotNull(cachedApiKeyDoc3);
        assertEquals("banner", cachedApiKeyDoc3.creator.get("principal"));
        
        assertSame(
            limitedByRoleDescriptorsBytes,
            service.getRoleDescriptorsBytesCache().get(cachedApiKeyDoc3.limitedByRoleDescriptorsHash)
        );
        
        final BytesReference roleDescriptorsBytes3 = service.getRoleDescriptorsBytesCache().get(cachedApiKeyDoc3.roleDescriptorsHash);
        assertNotSame(roleDescriptorsBytes, roleDescriptorsBytes3);
        assertEquals(3, service.getRoleDescriptorsBytesCache().count());
        if (metadata3 == null) {
            assertNull(cachedApiKeyDoc3.metadataFlattened);
        } else {
            assertThat(cachedApiKeyDoc3.metadataFlattened, equalTo(XContentTestUtils.convertToXContent(metadata3, XContentType.JSON)));