### 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boolean property, as well as the `expiration` property that contains the UNIX timestamp past of which the key is no longer valid for authentication.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/test/java/org/elasticsearch/xpack/core/security/action/apikey/GetApiKeyRequestTests.java
"username or realm name must not be specified when the api key id or api key name is specified",
                "only one of [api key id, api key name] can be specified" },
            { "username or realm name must not be specified when the api key id or api key name is specified" },
            { "only one of [api key id, api key name] can be specified" },
            { "neither username nor realm-name may be specified when retrieving owned API keys" },
            { "neither username nor realm-name may be specified when retrieving owned API keys" } };
        for (int caseNo = 0; caseNo < inputs.length; caseNo++) {
            try (
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                OutputStreamStreamOutput osso = new OutputStreamStreamOutput(bos)
            ) {
                Dummy d = new Dummy(inputs[caseNo]);
                d.writeTo(osso);
                ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
                InputStreamStreamInput issi = new InputStreamStreamInput(bis);
                GetApiKeyRequest request = new GetApiKeyRequest(issi);
                ActionRequestValidationException ve = request.validate();
                assertNotNull(ve);
                assertEquals(expectedErrorMessages[caseNo].length, ve.validationErrors().size());
                assertThat(ve.validationErrors(), containsInAnyOrder(expectedErrorMessages[caseNo]));
            }
        }
    }
    public void testSerialization() throws IOException {
        final String apiKeyId = randomAlphaOfLength(5);
        {
            final GetApiKeyRequest getApiKeyRequest = GetApiKeyRequest.builder().ownedByAuthenticatedUser(true).apiKeyId(apiKeyId).build();
            ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
            OutputStreamStreamOutput out = new OutputStreamStreamOutput(outBuffer);
            out.setTransportVersion(randomVersionBetween(random(), TransportVersion.V_7_0_0, TransportVersion.V_7_3_0));