### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
new String[] { "monitor" },
            new RoleDescriptor.IndicesPrivileges[] {
                RoleDescriptor.IndicesPrivileges.builder().indices("*").privileges("monitor").build() },
            null
        );
        Map<String, Object> roleARDMap;
        try (XContentBuilder builder = JsonXContent.contentBuilder()) {
            roleARDMap = XContentHelper.convertToMap(
                XContentType.JSON.xContent(),
                BytesReference.bytes(roleARoleDescriptor.toXContent(builder, ToXContent.EMPTY_PARAMS, true)).streamInput(),
                false
            );
        }
        List<RoleDescriptor> roleDescriptors = service.parseRoleDescriptors(apiKeyId, Map.of("a role", roleARDMap), randomApiKeyRoleType());
        assertThat(roleDescriptors, hasSize(1));
        assertThat(roleDescriptors.get(0), equalTo(roleARoleDescriptor));
        Map<String, Object> superUserRdMap;
        try (XContentBuilder builder = JsonXContent.contentBuilder()) {
            superUserRdMap = XContentHelper.convertToMap(
                XContentType.JSON.xContent(),
                BytesReference.bytes(SUPERUSER_ROLE_DESCRIPTOR.toXContent(builder, ToXContent.EMPTY_PARAMS, true)).streamInput(),
                false
            );
        }
        roleDescriptors = service.parseRoleDescriptors(
            apiKeyId,
            Map.of(SUPERUSER_ROLE_DESCRIPTOR.getName(), superUserRdMap),
            randomApiKeyRoleType()
        );
        assertThat(roleDescriptors, hasSize(1));