I'm a little confused by the question. When you say "high plan count" do you mean the number of plans in cache is high? If that's right, how are you establishing a low & high number there. Do you have a baseline.

Or, do you mean that the query is running long? If so, you need to look at the execution plan to understand whether or not it's selecting the index that you have. Also, since you're doing a SELECT * and you're going against a non-clustered index, you're going to be seeing RID or key lookups (depending on if you're dealing with a heap or a clustered index).

Or, do you mean that the estimated rows is high? If so, you need to update your statistics.