Which Tokenizer to use


Im kind of new to ES and doing some implementations on it.
This is regarding a performance improvement which we are trying to do in one of our projects.

I wanted to search for a phrase, ex., "my name is" in two to three source fields, all of those fields are mapped to an Analyzer which has lowercase filter and keyword tokenizer at present.
looks like Keyword tokenizer is taking more time compare to Standard tokenizer. Standard tokenizer gives us response in 200-300ms but KEYWORD takes around 2-4 secs.
so My questions are,

  1. is there a better way to enhance the performance using Keyword tokenizer?
  2. As the performance is good with STANDARD tokenizer, how can I make use of it to search a PHRASE? Standard tokenizer is good searching word by word but not as a phrase. Please someone correct me if Im wrong.

As we are running out of time, please someone help us here.
Thanks in Advance.