SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8598cce12320fcbda50c73facb9bfc8e3a423fadb5f40ebf844882087cf51b1f' 
  AND token = 'T/STY5WrWfnlWfwQB3lsTTr2SGB7Stc1JRv8OXfEhXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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