Mr McKay, 23, was attacked near a bus stop on his way home from work on Sunday, police said.
A 38-year-old man has been arrested in connection with the attack, which took place at 9.05 pm on St. Margaret Avenue in Delary.
Paramedics attended but Mr McKay was pronounced dead at the scene. Officers have called witnesses.
Before announcing the arrest, Detective Inspector Stephen McCulch said: “Our priority is to find the culprit as soon as possible and we need the help of the community to do so.
“So far the co-operation and response from the locals has been helpful to our investigation, however, we still need people to come forward with any information as this could be important for the inquiry.”
A 17-year-old boy was stabbed on Padden Avenue near St. Margaret Avenue on Saturday.
Mr McCulloch said the incidents were “not directly linked”.
He said: “With regard to this incident and as a result of extensive and ongoing inquiries in the local area following the serious attack on Padden Avenue, Daleri on Saturday night, we have followed the positive lines of inquiry in relation to each incident. Are
“We can confirm that while the incidents are not directly linked, we are continuing to investigate to establish the full extent of the situation.”
So far, more than 4,500 donations have been made to help his partner Chloe and her young son, Oscar.
Anyone with information can contact the police by calling 101 or Crime Stoppers anonymously on 0800 555111.