Pandas Explode on Multiple columns

I guess you need (note the difference in data for col4 which has None as OP mentioned):

pd.DataFrame([[i] if not isinstance(i,list) else i 
             for i in d1.values()],index=d1.keys()).T

---

    user paid  last_active  col4
0  user1    Y  11 Jul 2019  data
1  user2    Y  23 Sep 2018  None
2  user3    N  08 Dec 2019  None
3  user4    N  03 Mar 2018  None