10036: Label class <value> has an SQL query that references field names that are not indexed
Your layer has a label class with an SQL expression that references fields that are not indexed.
It's a good idea to index this field because it is used for querying features when drawing your map.
Solutions
Do one of the following:
Accept the display performance as is.
Review the draw metrics for this layer. If you are sharing the layer, review the data access metrics for the service. Learn about performance in ArcGIS Pro.
If you want to improve performance, index the fields reported to not have indexes. These fields are listed along with this warning. Learn about creating attribute indexes in the geodatabase.
Additional information
Attribute indexes can speed up attribute queries on feature classes and tables. For most types of queries, it is faster to look up a record on an indexed field than it is to search through the entire table.
Generally, you can improve overall performance using attribute indexes on key fields in your datasets.