### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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
if (omitted > 0) {
            sb.append("... (").append(total).append(" in total, ").append(omitted).append(" omitted)");
        }
        return sb.toString();
    }
    /**
     * package-private for testing
     */
    static XContentBuilder newDocument(
        char[] apiKeyHashChars,
        String name,
        Authentication authentication,
        Set<RoleDescriptor> userRoleDescriptors,
        Instant created,
        Instant expiration,
        List<RoleDescriptor> keyRoleDescriptors,
        ApiKey.Type type,
        Version version,
        @Nullable Map<String, Object> metadata
    ) throws IOException {
        final XContentBuilder builder = XContentFactory.jsonBuilder();
        builder.startObject()
            .field("doc_type", "api_key")
            .field("type", type.value())
            .field("creation_time", created.toEpochMilli())
            .field("expiration_time", expiration == null ? null : expiration.toEpochMilli())
            .field("api_key_invalidated", false);
        addApiKeyHash(builder, apiKeyHashChars);
        addRoleDescriptors(builder, keyRoleDescriptors);
        addLimitedByRoleDescriptors(builder, userRoleDescriptors);