SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce5797c8c2b735ba32630dd604341881923d1757d52fa15194b75adcd039dcdd' 
  AND token = 'lkHF7tNguT/8ntUpl7N5yvG4bfGuoEezdCV7Q47timI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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