It is tricky. The keres = to look for and kér = I ask for (politely) are considered different words (it may be useful to remember them together, being very similar)
the -és/-ás suffix means to turn a verb into a noun. So kérés = a request. The -es suffix is also used in a different way, but not on verbs. So keres is a root by itself, not derived from another word.