Use this code example to change the number of hours that an export table View to CSV link will be valid. This hook only deals with links for non-logged-in visitors.

add_filter( 'frm_export_view_link_expiration', 'frm_change_link_expiration_hours' );
function frm_change_link_expiration_hours() {
   return 72;
}

Change 72 to the number of hours you would like export to CSV links for non-logged-in visitors to be valid.