How do I get to my BIOS

There's probably some truth to that, but the root cause is a firmware setting.

Modern motherboards are no longer based on the antiquated BIOS firmware standard, they are based on the newer and nicer UEFI firmware standard. Many UEFI based motherboards include a set of technologies labelled "fast boot" which allows compatible operating systems to further bridge the gap between hibernation and a full shutdown.

Hibernation retains the user state of the system. When a PC is placed into hibernation, the contents of the volatile memory are written to disk (hiberfile.sys if you have it enabled) and when it is resumed the contents are read from the disk back into volatile memory. This includes the entire state of the machine, including the kernel state, device driver state, and the state of all user applications. The computer is restored to the exact state it was when it was hibernated.

When Fast Boot is enabled, a supporting operating system can first cleanly shut down the user applications (which account for the bulk of the volatile memory usage), and then hibernate the kernel and device drivers (which account for the bulk of the startup time). The justification for this is that the kernel and core device drivers are robust enough that they do not need to be fully reinitialized on every power cycle unless the hardware configuration changes in a way that can't be compensated for while running. Microsoft calls this Hybrid Shutdown; shutdown for the user space, and hibernation for the kernel space.

When restoring from Fast Boot the boot loader can simply restore the state of the kernel and device drivers rather than perform a full startup. Upon startup the firmware doesn't need to perform a full enumeration of all hardware devices because it knows that the hibernated OS kernel has already set itself up and has simply been suspended to disk. If you have an SSD installed, and all legacy support disabled, it will be able to POST and boot in the blink of an eye as you suggest. Naturally this can be problematic if one wishes to access the UEFI firmware settings, so most firmware implementations include a programmable splash screen delay which inserts a delay between POST and boot so that the user can press the necessary key to enter the firmware settings.

One of the major changes from BIOS to UEFI is the way the firmware handles the boot targets.

Under the BIOS standard the firmware enumerates devices for which it has basic block drivers (Floppy drives, ATA hard disk drives, ATAPI optical disks, USB mass storage devices, etc...), for which it has a built in ROM (PXE booting over network, platform storage controller), or for which it finds BIOS compliant ROMs (discrete storage controllers, RAID controllers). The user is responsible for prioritizing these devices in some sort of list. After POST, the firmware iterates through the list of devices and loads the first 512 byte block from each device into memory, and scans it for a valid Master Boot Record (MBR). If one is found, it passes execution to the boot loader code contained within the MBR; if one is not found, it proceeds to the next device in the list. If the list is depleted, you will see the infamous "System disk not found. Please insert system disk yadda yadda".

Under the UEFI standard the firmware scans all devices for which it has support (or can find support through a valid UEFI ROM), and then scans the device for either a valid Master Boot Record (if legacy support is enabled) or a valid Globally Unique Identifier Partition Table (GUID Partition Table / GPT). GPT is preferred to MBR in UEFI systems, and is required for storage volumes larger than 2.2TB. What UEFI does that BIOS does not do is actually scan valid GPTs for bootable volumes and enumerate those as boot targets. This allows UEFI firmware to enumerate valid bootable volumes on devices rather than potentially bootable devices which may or may not have bootable volumes on them. It does this all before the user is even presented with any sort of display, which is why the process can seem so incredibly fast. Combined with other advances found in UEFI, the entire boot process is many, many times faster than any BIOS based firmware.