That K in a Keystone is the Knox Glass Bottle Co....Date range 1932-1968....That 2 45 could be the date february 1945......Very Nice find...Ihave no idea what it was used for
I asked on a bottle forum I'm on and nobody seemed to know. It reminded me of some type of polish or witch hazel. I guess it also could be holy water but I found no exact matches anywhere. I've not dug any bottles like it.