SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f556f94a07087c69acb28b830bc77824cf3c65356fa6e771d6c791d9082b145' 
  AND token = 'ZTKr8JBYut+2nKmBuzxftV10/TAcwbgDjoYow5FGUrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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