SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a548b099bdc4f64f6d259264325eb350d23535341d8f694d0eef966875dbd4cd' 
  AND token = 'qqjmyiphHSd3+Ko7rRJEJcdNgtfRaArMsAMek0XdNbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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