### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
throw new UncheckedIOException(e);
        }
        return replaceLegacySuperuserRoleDescriptor ? maybeReplaceSuperuserRoleDescriptor(apiKeyId, roleDescriptors) : roleDescriptors;
    }
    
    static final RoleDescriptor LEGACY_SUPERUSER_ROLE_DESCRIPTOR = new RoleDescriptor(
        "superuser",
        new String[] { "all" },
        new RoleDescriptor.IndicesPrivileges[] {
            RoleDescriptor.IndicesPrivileges.builder().indices("*").privileges("all").allowRestrictedIndices(true).build() },
        new RoleDescriptor.ApplicationResourcePrivileges[] {
            RoleDescriptor.ApplicationResourcePrivileges.builder().application("*").privileges("*").resources("*").build() },
        null,
        new String[] { "*" },
        MetadataUtils.DEFAULT_RESERVED_METADATA,
        Collections.emptyMap()
    );
    
    
    
    
    private static List<RoleDescriptor> maybeReplaceSuperuserRoleDescriptor(String apiKeyId, List<RoleDescriptor> roleDescriptors) {
        
        
        return roleDescriptors.stream().map(rd -> {
            
            
            
            if (rd.equals(LEGACY_SUPERUSER_ROLE_DESCRIPTOR)) {
                logger.debug("replacing superuser role for API key [{}]", apiKeyId);