SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd16089cb3ec69b12c4349a65d8aa0992c24ee2536c15410da439297e68d7ca8' 
  AND token = 'axgIQ8peGi3DqrLeMW7fHOOWz4dPjDZPyX9C40NKqhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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