Preventing ngram on query

How would you disable the ngramming of the query term:
"match": {"username.ngram": "linus"

the indexer:
"tokenizer": {"customNgram": {"type": "nGram", "min_gram": 3, "max_gram": 5}

I don't want hits for lin, inu, nus as in Xinus but I do want hits for tlinustorvalds

In other words - I don't what the query term "linus" to be broken down to [4-2]-grams