If all else fails, you can always go to Mock::Quick and download the tarball yourself. This works for me, so most likely the problem is with the CPAN mirror you are accessing or your network connection to that CPAN mirror.

Manually installing a downloaded tarball can be done through either:

cpanm /path/to/Mock-Quick-1.111.tar.gz
[download]

or for cpan:

tar xzvf Mock-Quick-1.111.tar.gz
cd Mock-Quick-1.111
perl Makefile.PL
gmake test
gmake install
[download]