SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae3d159a36415983ecf4fc9a4af1fa972250213487b8d7796a3d3d2bbed23532' 
  AND token = 'Xtgkol4BIwcJGOdWhLsATJ+54T+ZzY2kT15n4mnpYfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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