Making dua or dhikr in the heart or mind, is moving lips a must? – Sheikh Assim Al Hakeem

I went to a place where no one can see me but mum came on the other side of the door before i started praying to grab clothes of the door. im not sure if she saw me or not but i felt riyaa inside. i didnt have time to look at my intention so i just prayed but i truly felt like i wasnt sincere for the first rakah maybe as i thought she knew i was praying then realised Allahs watching and tried.