Log slow SELECT queries only I'm enabling slow log query for MySQL but I notice that CREATE, INSERT, UPDATE, et. al are also included.
I'm generally not interested in those.
Is there any way to specify that only slow SELECTs are to be logged?
No.
Instead, I suggest that the most important information comes from summarizing the log.  This can be done via either of these

pt-query-digest
mysqdumpslow -s t

Then focus on the first few entries.