Clear Example for drush rsync exclude paths
drush rsync has an  --exclude-paths parameter that will allow you to exclude your node_modules directory.

Have a look at the parameters for rsync. 

You should be able to do something like :

drush --exclude-paths=sites/all/themes/themename/node_modules rsync @self @live 


Because the Drush rsync command uses strict option handling, the --exclude-paths option must appear before the rsync command name.