Honestly, the short answer is your seedling looks healthy and is doing well! 👍
The long answer for those curious about the plant science is that with your Mars Hydro LEDs radiant heat won't be an issue, and they are probably not maxing out the PPFD (photosynthetic photon flux density) that the plants can handle. Too much light can cause photosynthesis to outpace the carbon dioxide as a limiting factor, and can begin to damage the plant, but I don't see anything like that happening. Even though the plant is looking pretty good, I would try to raise your humidity just a little bit to 60 or 70rh With a low humidity, the vapor pressure deficit (VPD) the plant can take protective action and begin to draw less moisture and nutrient and therefore have a slower growth and a higher tendency to nutrient burn.
Hope that helps, and happy growing!