Aho Corasick doesn't seem likely to be useful here; it's good if the haystack is huge (or you have many haystacks to search) and you have many needles to look for (and the needles never change), but it pays a fairly steep setup cost; for a utility that searches for a single subsequence once, with no history, Aho-Corasick wouldn't help much.

A variant on Boyer-Moore (which involves less preprocessing work on the needle) might help, but I'm not sure the feature is compelling enough to warrant acceleration in the first place.