Create a survey with a question with more than one option
Enable the "Token-based response persistence"
Enable the "Participant may save and resume later"
Create a token and publish the survey
Open the survey link and enter the token
Answer the question and click in "Resume Later"
Check the response table. Don't close the survey.

• The answer is correctly saved
  Go back to the survey page, change your answer then click Resume Later again.
  Check the response table again.
• The answer is correctly changed.
  Close the survey page. Open the link again and type your token
  Change your answer and click on Resume Later
  Check the response table
• The response is not changed.
  Go back to the survey and click on Submit
  The page says the survey was submitted and the data was saved.
  Check the token table
• The token is used. The completion date field is filled.
  Check the response table
• The partial answer is still there, but uncompleted

So, its not possible to complete the survey.