How do I sort by a specific order

Question

Table users:

id | firstname | lastname
---+-----------+---------
 1 | John      | Smith
 2 | Adam      | Tensta
 3 | Anna      | Johansson

I want to select these in the order of ID 2, 3, 1. ONLY specified by the id-field. Is this possible?

I'm thinking something like SELECT * FROM users ORDER BY id ORDER(2,3,1)

Can this be done, and in that case how?