SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36fa6f39467ab8fe425019d12ed5138a890ef5cb2fc9cf1aeccba220ec7ec4f1' 
  AND token = 'xUXYwZY1NXKpBhwk5SkP+iFY2khqvRAyeGmPEtEl/AY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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