private String expClaimText(long lifetimeSeconds) {
        return claimOrHeaderJsonText("exp", time.milliseconds() / 1000.0 + lifetimeSeconds);
    }
Add and validate all the configured extensions.
 Token keys, apart from passing regex validation, must not be equal to the reserved key {@link OAuthBearerClientInitialResponse#AUTH_KEY}
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/internals/unsecured/OAuthBearerUnsecuredLoginCallbackHandler.java