How to apply Spring Security filter only on secured endpoints?

I have an application with the same requirement and to solve it I basically restricted Spring Security to a given ant match patter (using antMatcher) as follows:

http
    .antMatcher("/api/**")
    .authorizeRequests() //
        .anyRequest().authenticated() //
        .and()
    .addFilterBefore(authenticationTokenFilterBean(), UsernamePasswordAuthenticationFilter.class);

You can read it as follows: for http only invoke these configurations on requests matching the ant pattern /api/** authorizing any request to authenticated users and add filter authenticationTokenFilterBean() before UsernamePasswordAuthenticationFilter. For all others requests this configuration has no effect.