Your entity model has the combination of the two properties FTPRuns.ID and FTPRuns.LastRun as entity key while your table has only the column FTPRuns.ID as primary key. So in your model you specify that the combination of FTPRuns.ID and FTPRuns.LastRun must be unique while your database has the stronger requirement that FTPRuns.ID alone must be unique.
Just exclude the property FTPRuns.LastRun from the entity key. Maybe this happened accidentally or the Entity Framework could not get primary key information from the database and had to infer the entity key. For example views have no primary key and the Entity Framework will infer the entity key as the combination of all non-nullable columns.