MySQL query on medium-sized table fast on one system, slow on another

I have the following table with about 40k rows:

CREATE TABLE IF NOT EXISTS `log_ui_activity` (
    `uiActivityLogEntryId` INTEGER UNSIGNED auto_increment ,
    `uid` INTEGER UNSIGNED,
    `from` DATETIME,
    `duration` INTEGER UNSIGNED,
    `nCharactersTyped` INTEGER UNSIGNED,
    `nClicks` INTEGER UNSIGNED,
    `hadOtherInteractions` INTEGER UNSIGNED,
    `currentPage` TEXT,
    `currentPageArgs` TEXT,
    `currentPageStateInfo` TEXT,
    `createdAt` DATETIME NOT NULL,
    `updatedAt` DATETIME NOT NULL,
    PRIMARY KEY (`uiActivityLogEntryId`)
) ENGINE=InnoDB;

with two additional indices, each on createdAt and uid.

When I run the following query:

SELECT *
    FROM log_ui_activity
    WHERE `createdAt` IN (
        SELECT MAX(`createdAt`) FROM log_ui_activity
                  GROUP BY uid);

It finishes within 0.2s on Windows 7 and running XAMPP with:

MySql Ver 14.14 Distrib 5.6.20, for Win32 (x86)

However, it takes several minutes when running the exact same query on an exact copy of the data on a Mac Pro (verified: structure, indices and engine are all the same) running MAMP with:

MySql Ver 14.14 Distrib 5.5.38, for osx10.6 (i386) using EditLine wrapper

I have even tried different clients...

Any ideas how the query can be so much slower, even though everything is/appears to be identical?

UPDATE

As suggested in the answer, using JOIN instead of IS IN fixes things. For reference, this is the JOIN statement:

SELECT *
    FROM log_ui_activity a
    INNER JOIN (
    (SELECT MAX(`createdAt`) createdAt FROM log_ui_activity GROUP BY uid) tmp
    )
    ON (a.createdAt = tmp.createdAt);