public ExpirationPolicy toTicketExpirationPolicy() {
        val simple = casProperties.getAuthn().getMfa().getSimple();
        return new HardTimeoutExpirationPolicy(simple.getToken().getCore().getTimeToKillInSeconds());
    }
To ticket expiration policy.

@return the expiration policy
support/cas-server-support-simple-mfa-core/src/main/java/org/apereo/cas/mfa/simple/ticket/CasSimpleMultifactorAuthenticationTicketExpirationPolicyBuilder.java