Disable the zooming keyboard shortcuts in RStudio

RStudio provides the option to use CTRL++ to zoom in on the whole workspace and I often hit that combination by accident, when I would like to execute selected code with CTRL+Enter. This is wasting time and I need to zoom out again afterwards. So I would like to know if there's the possibility to disable these keybindings. These keyboard shortcuts are not available to edit under Tools - Modify Keyboard Shortcuts. Rstudio version 1.1.456.