SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b269c2b79fc226fdedb8bb388b417d72b8b80a3b83a8a250a029ee56cb4dc219' 
  AND token = 'bLbtt+1zG8QjwKPHx6QjJoQAd/1KpgTWto+QTxIH+ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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