how do I check the last time dbreindex or an index defrag was executed
Try one of the queries below and see if that is what you are looking for:

SELECT OBJECT_NAME(OBJECT_ID) AS DatabaseName, last_system_update,*
FROM sys.dm_db_index_usage_stats
WHERE database_id = DB_ID( 'YourDb')
AND OBJECT_ID=OBJECT_ID('YourTable')


select name as index_name,
         stats_date( object_id, index_id) as stats_update_date
from  sys.indexes
where object_id = object_id('YourTable');


Select * 

From sys.dm_db_index_usage_stats