--default-cache-ttl n
  Set the time a cache entry is valid to n seconds.  The default is 600 seconds.
--max-cache-ttl n
  Set  the  maximum time a cache entry is valid to n seconds.  After this time a cache entry will be expired even if it has been accessed recently.  The default is 2 hours (7200 seconds).

keychain --clear --agents gpg

echo RELOADAGENT | gpg-connect-agent