SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5395cb871f7374b73d2e14ceaa9d7d6953d8baff8bfa3b2e55aa119ca76d6839' 
  AND token = 'xvrWaJlU+walvQHp9aM4AsWnChxk7YLYLNk5MLtdqm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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