The HANDLER statements give you direct access to reading rows from the storage engine. This is much faster than normal access through SELECT as there is less parsing involved and no optimizer involved.

In MariaDB 5.3 you can used prepared statements for HANDLER READ, which should give you a speed comparable to HandlerSocket. Also see Yoshinori Matsunobu's blog post Using MySQL as a NoSQL - A story for exceeding 750,000 qps on a commodity server.