RoW

idk anymore, seems some coutries are on that list in some cases but not others.. the only ones that are almost always included in that list is EU/NA countries.. but even then there are exceptions. what game?

SEA Locked stuff should be appropriate for your location (assuming steam profile is accurate)

Does it state on the site which countries it can (or can't) be activated in? If it says it won't work in your country, then you wouldn't even be able to redeem the key. Also, what is the site you're talking about and what game is it about? This information could help determine this situation.

From what I know ROW is region-free and uncensored. But I guess steam can still have an activation lock on it so it cant be activated in certain countries.

Game companies often sell games at a lower rate in less expensive markets, like Russia, South America, or South East Asia. In order to prevent someone from a more expensive region to take advantage of the internet to buy the game at a lower rate, games purchased in those cheaper markets may be region-locked, so they can only be activated in said region. This is distinguished from versions of the game that are not locked to those regions, which can be activated in "Rest of World" or "RoW".
Generally speaking, a RoW key can be used anywhere in the world, whereas a region-locked key can only be used in the appropriate region.

However, that's not the full story, and there are a few more things to consider.
1) Due to censorship laws in some countries (e.g. Germany) a modified version of the game may only be available there, in which case a RoW key might not activate in the specific region.
2) Sometimes a publishing deal means that a game may be sold by different companies in different parts of the world. This is predominantly the case in eastern Europe. Then, similarly, a key might be region-restricted, because a key purchased from Publisher A would violate Publisher B's exclusive right to sell the game in the other country.
3) Some companies just opt for a very convoluted region-restriction scheme that defies logic (to us outsiders). Deep Silver is the main culprit here.

So, generally speaking, a RoW key will work anywhere. Except it may not.