-mtime
é usado por dias, se você precisar de 2 horas, verifique isso:
find /tmp/something -type f -mmin +120 -exec cp '{}' /tmp/target \;
mmin especifica os minutos, então -mmin +120 irá filtrá-los há mais de 120 minutos (2 horas). Do manual:
-mtime n
File's data was last modified n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file modification times.
-mmin n
File's data was last modified n minutes ago.