SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0c7971a94746b10acd9ead08984b233e8247fb9bb77a3dfc500f031502f268f' 
  AND token = 'MFdrUCXmwz+cF2NbqKC1L8XR3hBY++4d2YhzdZDUUFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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