SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdff0afe5be986d819b13491a6c28653b09d518f7fcd958666a437e9c4057ab4' 
  AND token = 'u3JFvoIPL9wFCpq4GKKniQ9JNYkFyXgfVXt3RxvLCoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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