ES 5.0 - case insensitive search for keyword fields

I've added a custom analyser:

"analyzer": {
"folding": {
"tokenizer": "standard",
"filter": [ "lowercase", "asciifolding" ]
}
},

I've also added a dynamic template in order to set the datatype of my fields. I've the following for keyword.

{
"string_as_keyword": {
"match_mapping_type": "string",
"match": "*_k",
"mapping": {
"type": "keyword",
"analyzer": "folding"
}
}
},

Is that correct? How can I query my data? I've found a lot of information about older versions but not for 5.0.