SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e887271d0cd84cb09b0b46578e232d07c467aa715d52cb2ee1969da53e64f50' 
  AND token = 'a/G9QO+VoglkVjivQHOfMY05AH3/7hIzBqX19lieeCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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