I have the database in this format.

    CREATE TABLE `dna` (
     `p_id` bigint(20) NOT NULL AUTO_INCREMENT,
     `dna_bits` bit(32) NOT NULL,
     `user_id` int(11) NOT NULL,
     PRIMARY KEY (`p_id`),
     KEY `dna_bits` (`dna_bits`)
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1

Currently, I have 100 millions rows and I need to query quickly by dna_bits which I have an index on. 

My query looks like

    select CONV(dna_bits, 16, 2) as bits, user_id from dna where dna_bits in (....)

Searching 10000 dna_bits in where clause took me over 8 seconds.

EXPLAIN on my shorten* query showed this.

    id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
    1	SIMPLE	dna	range	dna_bits	dna_bits	4	NULL	77	Using where

I'm running MySQL server on my iMac 3.2 GHz Intel Core i5 with 16GB RAM.

What can I do to speed up the process?

Thanks.