SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d9888e763cadea729c9f04255fc69e09d754a102be077e5490ab40e6cced437' 
  AND token = 'H5To287jtMmjihMl2GijBHYPmcQWHRcKrzEalVYnHo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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