As someone who just a week ago implemented a similar thing: SMS sucks. Sending it can take any amount of time it seems. Sometimes <10s sometimes a minute or mor

As someone who just a week ago implemented a similar thing: SMS sucks. Sending it can take any amount of time it seems. Sometimes <10s sometimes a minute or more and unless you get a report from your provider you don't know which it was. The only reasonable solution was to adjust the timeout of the sent token.