Sorry, it is just an average copper plated zinc Cent. A little reading on the differences between business strike and proof coins would be advised. https://www.thesprucecrafts.com/strike-type-definition-768693

Backing up what Paddy, Potty, 'pat and L are saying, it's unfortunately not a proof. Not only is it Denver mint, but it has a rough field. A proof would have a smooth mirror-like field. https://www.usacoinbook.com/coins/591/small-cents/lincoln-memorial-cent/1990-S/

Welcome to CT @Anto Yeretzian. You have already gotten the correct answer, but I have to ask; What makes you think or see, that leads you to believe it could be a proof coin? All I see is a shiny crappy Zincoln cent, but maybe that's just me.