Can I pay for 2 Miro Premium accounts with a single payment and separate login access?

This sounds like a regular account setup. 

What problem are you trying to solve for?
e.g. Two accounts for yourself, at your existing email box
e.g. Two different people.
 

e.g. Have two accounts for yourself, at your existing email mail-box.

Use two different email addresses, or add an alias to your email address, or use + addressing. 

Tip: “+” (Plus) addressing is supported by most email systems.
i.e. name+topic@domain.com will arrive at the same email box as name@domain.com.
e.g. name+miro1@domain.com and name+miro2@domain.com will arrive at name@domain.com, setup two accounts that ay. 

e.g. Two different people

• Setup your account
• Setup your payment information
• Create a team (workspace)
• Add a new person to the team.

You now have two people in your team, and you pay for both.

yes you can but you have to login accounts in different devices