What are some likely causes of high Client:ClientRead AAS in AWS RDS?

I have a particular query, its a simple select with an inner join. Seems to be pretty well indexed. But it's registering as a worst offender in performance insights. With a 0.13 on CPU and a 4.5 on Client:ClientRead. All the documentation and articles I can find indicate this is common for bulk data copying. But I don't think this is the case. Since it's such a basic select. It's being called around 70 times per second. Which isn't even that high compared to others I have in the 500 calls per second, and it's only serving back about 7 rows, 10 columns each. So other than bulk data copying, what other factors might be giving me a high AAS for clientRead?