EditorSceneShortcuts.cs

using UnityEngine;
using UnityEditor;

public class EditorSceneShortcuts : MonoBehaviour
{
	// Edit this line to define your shortcut in the editor
	// In this example, #1 is the shortcut
	//	% = ctrl (win) or cmd (osx)
	//	# = shift
	//	& = alt
	//	_ = no key modifier
	[MenuItem ("Scene Shortcuts/Edit Scene1 #1", false, 0)]
	public static void EditScene1()
	{
		if( EditorApplication.SaveCurrentSceneIfUserWantsTo() )
			EditorApplication.OpenScene("Assets/Scene1.unity");
	}

	// Each scene should have its own function + shortcut. Make sure to replace Scene1, Scene 2 etc
	// This function is just here to show you what to duplicate
	[MenuItem ("Scene Shortcuts/Edit Scene2 #2", false, 0)]
	public static void EditScene2()
	{
		if( EditorApplication.SaveCurrentSceneIfUserWantsTo() )
			EditorApplication.OpenScene("Assets/Scene2.unity");
	}
}