Token validity times

Having set my survey to closed and enabled token response persistence, every time a user tries to answer the survey, the relevant token is automatically generated and stored in the limesurvey token table. However, the time that the token remains valid is automatically generated and is incorrect stopped the user from answering the survey. I would like to have control over the time the token remains valid without having to individually reset each token as a user tries (unsuccessfully) to answer the survey.