Yes, it is quite likely that Macskay is a varraint of Mackay surname.
This is paraphased but you can get the point:
As Clans 2014 puts it: Mc or Mac? Mc is Irish and Mac is Scottish. Or is it the other way round? Actually, it's neither - McNaewhere (and for that matter M'Naewhere) are just abbreviations for MacNaewhere. The Mc or Mac form may have become fixed over time in one particular branch, but it does not signify origin. Also, don't fret over variants - a McKay is a Mackay is a M'Kay is a McCay is a Mackey is a Makee is a Makey, and all are derived from MacHugh (Gaelic, MacAoidh).
If the following surnames in the Mackay DNA Surname project are varaints, I do not see why Macskay wouldn't be a fit. Coy, Kee, Kees, Key, Kies, MacCoy, Mackaay, Mackay, Macke, Mackey, Mackie, McCoy, McIe, Mckay, McKee, Mckoy, Mikkenie
Greg
As Clans 2014 puts it:
Mc or Mac? Mc is Irish and Mac is Scottish. Or is it the other way round? Actually, it's neither - McNaewhere (and for that matter M'Naewhere) are just abbreviations for MacNaewhere. The Mc or Mac form may have become fixed over time in one particular branch, but it does not signify origin. Also, don't fret over variants - a McKay is a Mackay is a M'Kay is a McCay is a Mackey is a Makee is a Makey, and all are derived from MacHugh (Gaelic, MacAoidh). - See more at:
http://mackayproject.cundiffgenealogy.org/#sthash.tGKFP0sJ.dpuf