### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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/core/src/main/java/org/elasticsearch/xpack/core/security/action/apikey/GetApiKeyRequest.java
return this;
        }
        public Builder apiKeyId(String apiKeyId) {
            this.apiKeyId = apiKeyId;
            return this;
        }
        public Builder apiKeyName(String apiKeyName) {
            this.apiKeyName = apiKeyName;
            return this;
        }
        public Builder ownedByAuthenticatedUser() {
            return ownedByAuthenticatedUser(true);
        }
        public Builder ownedByAuthenticatedUser(boolean ownedByAuthenticatedUser) {
            this.ownedByAuthenticatedUser = ownedByAuthenticatedUser;
            return this;
        }
        public Builder withLimitedBy() {
            return withLimitedBy(true);
        }
        public Builder withLimitedBy(boolean withLimitedBy) {
            this.withLimitedBy = withLimitedBy;
            return this;
        }
        public GetApiKeyRequest build() {
            return new GetApiKeyRequest(realmName, userName, apiKeyId, apiKeyName, ownedByAuthenticatedUser, withLimitedBy);
        }
    }
}