SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb279e36178032e26c66710bda9191c43a42d416502eb14e4fff7bd600950f3' 
  AND token = 'lX4oIYHhn38kk3xUIPfntY8HKld+ZIYH2QQ+cGCbzQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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