SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e99fa67843bad9147bacd15abc2ac811956d316e8439a9ae807c04e8fe2501e3' 
  AND token = 'DFjbeVIggkq5Qm/MkaFkP9DzTfYAZe0L5rZBvOwKXqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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