SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '517115a397ed6a4a28c509df0f476216c456e0efa2f6aeb8e9f45b481e79966f' 
  AND token = 'YuIgiuWSxPpBOdSChugnlyY2k370JnLklCCX0Ivs9rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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