SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f829173b29f831ba82a5685021b4350f5dc898fdf920264ed1c08a6acf291214' 
  AND token = 'yUETWBArqVsS5v96FD3YGT+MbOtNSrgyjo4Y7MxdR60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}