SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef3250fdab98f180adc4b03559495c6acdcc3ae432e255c872bc3b45f96886e2' 
  AND token = 'xpmLWPamA9Szh3zj/yYHfRvT4I5pVndCHtsbqpTcmsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}