SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355f2d2a790a9af43efd9f330834a988e7ad54fb18bc3b648f54ba9c3fb441d8' 
  AND token = 'H5XmU/OI8pTXZdAwsjXV1VYi3AgZBiz1y4jMSpYJHZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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