SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17d615e0014e0442be7d43af24ceec1599ee15853ee031217304ad1ed3167455' 
  AND token = 'oLJcXkgGzG+WTV3eGmEVDdhYWn2+bkXY6B45LZQaMxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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