SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b7023167b63d36964eafda97ce72441bb7be36aab6f0a88964a2bffb0c681f' 
  AND token = '8e6O+DwDCnDJv5m6gW7v6O14jjc2CvGcUjPpZw4B6i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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