I am unable to use smarty in CKeditor because it's transforming the ' into & #39; I couldn't find anything useful when click the configure CKEditor Button in display preferences.
You can turn off html encoding for CKeditor through UI (i.e >= 4.7)
Navigate to Administer >> Customize Data and Screens >> Display preferences
Scroll down until you see
Configure CkEditor button. Click on it to view all the settings. Under Advance options add
entities option as
False(as shown in image) and save the form.
Note: You will need to clear your browser cache to reflect the changes(and CiviCRM caches).