ZK will soon use an internal keybinding system.
You can find the file at Spring/LuaUI/Configs/zk_keys.lua
You can add keybinds to this file in your preferred order. To bind more than one key to an action, use this format:
{ "attack", {"a","q","c+w"} },
This will bind A, Q and Ctrl+W to all be attack. But if you update hotkeys in the menu system inside the game, it will unbind all hotkey combos and only apply the hotkey combo you pressed, then save.