SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08d073ef1bace075d9bf7ee41317ff0cc1a06432840f2ee31412acfce4e243fc' 
  AND token = '+15TkcdU7nAb2cZxvWfOzHEX+9Lp/Pj1Y3jFLcXISkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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