SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34cac087b55051e43df6b09ba0921e268bd34903ef726b39a04572c6f6aecb71' 
  AND token = 'iLjuHnoZz8i86OD2GfXIGai8RelZTVBdKUTyyoNEEjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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