According to The Book, angels are low density creatures and that God created them originally from light. They move at any speed from zero up to the speed of light. It is the angels who carry out God’s orders. Those angels take their orders from a Preserved Tablet somewhere in outer space, and not from God’s Throne.
They commute to and from this Preserved Tablet to get their orders from God. In the following verse, the Quran describes how angels travel when they commute to and from this Tablet. And the speed at which they commute to and from this Tablet turned out to be the known speed of light:
Surat As-Sajdah (The Prostration) – سورة السجدة
يُدَبِّرُ الْأَمْرَ مِنَ السَّمَاءِ إِلَى الْأَرْضِ ثُمَّ يَعْرُجُ إِلَيْهِ فِي يَوْمٍ كَانَ مِقْدَارُهُ أَلْفَ سَنَةٍ مِّمَّا تَعُدُّونَ
“He arranges [each] matter from the heaven to the earth; then it will ascend to Him in a Day, the extent of which is a thousand years of those which you count.” | QS 32:5
It is the angels who carry out these orders. Those people back then measured the distances neither in kilometers nor in miles but rather by how much time they needed to walk. For example, a village two days away meant a distance equivalent to walking for two days; ten days away meant a distance equivalent to walking for ten days.
However in this verse the Quran specifies 1000 years of what they counted (not what they walked). Those people back then followed the lunar calendar and counted 12 lunar months each year. These months are related to the moon and not related to the sun. Hence in 1 day the angels will travel a distance of 1000 years of what they counted (the moon).
Since this verse is referring to distance, then God is saying that angels travel in one day the same distance that the moon travels in 12000 lunar orbits. We discovered that in an inertial geocentric frame 12000 Lunar Orbits/Earth Day is equivalent to the speed of light.