Is it possible to buy a KM (Koleje Mazowieckie) ticket on the train in warsaw?

I was looking for the fastest way to go from warsaw central train station to warsaw airport ,and it appears that this would be the train KM9 .

I know where to get the train ,but problem is ,I should arrive around 2:50 pm to warsaw ,and the KM9 train leaves at 3:10 pm .
So I don't have much time to search for a place to buy the tickets from .
Does anyone know if it's possible to buy the ticket inside the train ? if not ,do you know where I can purchase it ?

There are often ticket machines on the train. But you can buy tickets from any Relax shop at the station (or other newsagent type shop there). You don't need to queue up to get a ticket from the main ticket office (in fact from memory those ticket windows don't even sell the ticket you need).

From KM website

On the train

Purchasing a ticket on the train

For the convenience of the Mazowieckie Railways passengers, there exists the possibility of purchasing a ticket directly on the train. Any traveller without a valid ticket for his journey or having a ticket that is not legalised/not activated should enter the train through the first door of the train (at the head of the units), and notify the train manager for the purchase, legalisation or activation of the ticket.

mazowieckie.com.pl/en/buy-activate-ticket/on-the-train.html