Unexpected Operand should contain 1 columns error

I have a table, exposure, which looks like this:

+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| src        | varchar(20)   | NO   |     | NULL    |       |
| instrument | varchar(10)   | NO   |     | NULL    |       |
| result     | decimal(12,3) | NO   |     | NULL    |       |
| instant    | bigint(20)    | NO   |     | NULL    |       |
+------------+---------------+------+-----+---------+-------+

This table is used to store historical exposure values, and is expected to contain the occasional gap. I'm trying to select, for a given src and instant, all (instrument, result, instant)'s either at that target instant or at the largest instant smaller than the target instant. The following SELECT statement does exactly that.

SELECT * FROM exposure AS e 
    WHERE e.instant = (SELECT MAX(instant) FROM exposure 
        WHERE instant <= 1396985195077 
        AND src = 'testSrc') 
     AND e.src = 'testSrc';

However, when I try to specify the columns I wish to select as in the following query, MySQL responds with ERROR 1241 (21000): Operand should contain 1 column(s). I suspect it is confusing the inner and outer queries.

SELECT (e.instrument, e.result, e.instant) FROM exposure AS e 
    WHERE e.instant = (SELECT MAX(instant) FROM exposure 
        WHERE instant <= 1396985195077 
        AND src = 'testSrc') 
     AND e.src = 'testSrc';

My MySQL version string is: Server version: 5.5.34-0ubuntu0.13.04.1 (Ubuntu).

Change your SELECT (e.instrument, e.result, e.instant) to

SELECT e.instrument, e.result, e.instant 
FROM ..

using columns in () mysql identifies it as any operation to perform thus there are multiple columns you get an error that there should be one column if you still wanna use parenthesis you can select your columns as

SELECT (e.instrument), (e.result), (e.instant) 
FROM ..