SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '693e79b754b035f7b4a49b2014f2efc58c504eb9f9ed1f8b8daf76eb6c400bca' 
  AND token = 'tGFXldG76Rq/5rP+rLbXpeK7hhYY0jfUWb3vHHj3CzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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