SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '381731f6e84efc47f816be38f0cd6e56de52580792b21a4e9ccd784db7196326' 
  AND token = 'aToZmjRYso7JYgbTUHPS2q/KXT/CwkTBG1NMkvC+JwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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