SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f103cc3deb76f560eadd2d8a47941747f1efd24f38d92fc6077b852ada523414' 
  AND token = 'OkQLQOMg8mFJ6+L86wlVNqGdFkMc/sjvDwZ8acmjmGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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