Is the Lexus LX expensive to maintain?

Yes. The Lexus LX is a premium luxury SUV, so maintenance costs are higher than those of most regular SUVs.
Typical service costs are:

Minor service: Around Rs. 28,000–Rs. 45,000

Annual maintenance: Around Rs. 50,000–Rs. 80,000, depending on usage and service requirements.

Do note that these costs are indicative and actual costs may vary depending on your location, service requirements and replacement parts.