There's a difference of one kanji between the two words, and the meaning is close enough that I'd almost say these are interchangeable words. However, I'm still curious to know what difference, if any, exists between these two terms.
検索 means "to search in Google / e.t.c." (mainly by using a computer)
探索 means "to search something in a big and open space (e.g. for treasure or a culprit).
You can find more here: http://honnowa.exblog.jp/8301459/
検索 = search index or look over
探索 = more like explore