I would like to know where to look for registers of birth, marriage and death for a village in Slovakia. The village is called Vyšný Kručov (Krucso in Hungarian). It is found between Presov and Bardejov.
That type of information is found in gazetteers.
There is an English tabular version of Dvorzsák's 1877 work on the Wayback Machine: https://web.archive.org/web/20160327063819/http://www.radixhub.com/radixhub/gazetteers/1877
The page numbers column links to the University of Pécs's digital edition, but you have to remove the Wayback Machine parts from the URL. https://kt.lib.pte.hu/cgi-bin/kt.cgi?konyvtar/kt03110501/0_0_1_pg_504.html
What's especially handy in the archived page is that if you click the placename and then click through to the 1913 gazetteer, it'll tell you the current name of the place.
Dvorzsák is organized first by county, which can be handy if you're trying to decipher the name of a nearby place (i.e., you know the county but not much else), but if you only know the place and not the county, then one of the later official gazetteers might be a better starting point. The Central Statistics Office has scans of them: https://www.kshkonyvtar.hu/article/56/959/helysegnevtarak
The 1913 edition is a largish PDF; it's best to download it and save it on your computer. (I generally have it open. There's always something to look up in it. [Although I happen to know the county for Eperjes without needing to look it up.])
For Krucsó, the answer to your question is that Roman Catholics were recorded in Kaproncza (later Magyarkaproncza, now Koprivnica), Greek Catholics were recorded in Stefuró (later Istvánd, now Štefurov), and Lutherans were recorded in Margonya (now Marhaň).