Hello Vera Bangs,
I’m sorry the verification code is arriving too late to use. That means you’re blocked at Microsoft account sign-in, before you can view any recovery key saved there.
If the sign-in screen offers another verification method, please try that. Otherwise, the way around this page is to check whether the BitLocker key was saved elsewhere, such as a printout or USB drive, or in the Microsoft account of someone who set up the device.
If none of those applies, unfortunately I don’t know of a way to bypass account verification to view a key stored in that account. Microsoft Support also cannot retrieve or recreate the BitLocker key.