This was published in the Comic-Con International San Diego 2013 Souvenir Book last summer.
Ken's art is printed on page 52 in the Superman 75th Anniversary section. It is the bottom right corner quadrant.
Disclaimer: The images in this publication are copyrighted by 2013 San Diego Comic Convention and are only being shown here to document Ken's list of published works and not for financial gain. Please see the inside cover of the book for full copyright information. This was not a sponsored post.