For completeness sake here are a few more ways of doing that:
find -maxdepth 1 -type f -iname '*key*' -not -name '*~' -exec cat {} \; | sort
find -maxdepth 1 -type f -iname '*key*' -not -name '*~' | xargs cat | sort
cat $(find -maxdepth 1 -type f -iname '*key*' -not -name '*~') | sort