1. Now of all times: justo agora, logo agora
The expression "of all times" means of all possible times, the set of all moments something could have happened. So, "now of all times" suggests that now is the worst time of all the possible times. - English.stackexchange.com
Of all (the): informal — used in phrases to express surprise, disapproval, anger, etc. - Merriam-Webester's
- Why did my car break down now of all times, when I can least afford it?!
2. Today of all days: justo hoje, logo hoje
"Today of all days" is an expression meaning "this is the worst day for this to happen" or "how ironic that this happened today." For example, Jenny went to work wearing old clothes that didn't fit her well, her hair didn't look good and she was in a bad mood. Her coworker tells her, "Hey, my cute brother is coming to take me out to lunch today. Wanna come and meet him?" Jenny says, "Ugh! Today of all days! Why couldn't it be tomorrow?" - Wordreference