SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b28587b82cd603e3e5365d290a4366508aec35a2f0a7066b834ccfdfae62f4' 
  AND token = '7r65Zv6hDyzHXnGMryognbn2JvSeFXjRqeylFjAux9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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