The Pre button toggles the preformatted style on the selected text or the current line (applies <pre> tag to blocks).
The Code button toggles the code style on the selected text or the current word (applies <code> tag to inline elements).

The default shortcuts for the buttons are:

• Ctrl+Q – Pre
• Ctrl+D – Code

In the admin Settings submenu it’s possible to change these shortcuts.
Press a key combination in the text fields with the Ctrl key included and the text will be filled automatically. Or you can type it manually.

Some combinations may conflict with the default editor or browser shortcuts.
So check them on your instance.

You may use these types of shortcuts:

• Ctrl+B, .., Z (except AXCV)
• Ctrl+0, .., 9
• Ctrl+[symbols] (-=`[];'\/,.)
• Ctrl+F1, .., F12
• Ctrl+Pad0, .., Pad9
• Ctrl+Pad/, Pad*, Pad+, Pad.
• Ctrl+Shift+...
• Ctrl+Alt+...
• Ctrl+Shift+Alt+...

This plugin GitHub repository: https://github.com/mortalis13/tinymce-code-formatting.