Unfortunately, Dalton has not been seen in several months so this plugin seems to be unmaintained.
However, there is a workaround with
Action Chains, if you don't mind sticking to using the same keyboard shortcut.
You can use a chain with Calibre's "View" and a single-field edit to update your #lastread column to the current datetime. You can import the attached file to AC to test it out (context menu in 'add/modify chains'); there's also a condition attached to prevent accidental mass-opening books.
Then bind that to a key; personally I just unbound the default 'view' key (V) and set it to that.