It doesn’t look like it’s possible to check a user’s exact read time? Currently it only shows minutes, days, months, etc.
What about, when hovering over the read time on a user’s profile, it shows their exact read time, like 8d, 2h, 38m, for example?
The json load for /admin/users/list contains that rounded-off time, so it’s not trivial (e.g., just a CSS tweak) to get this data. It’s not clear that knowing someone has read 2 days and 23 minutes is that different from 2 days.
If it’s really important, you could get the data with the data explorer plugin.