SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '826448ed243c7452ecfbdf35191bdfca2735bddb30f306e27e50c5a82f894ee4' 
  AND token = 'MBFltB/VKsDx8smwj0HZxYOUaG6kY26ylyS/OgRW8j0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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