SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f36a39d058266fe301c3276aaa1720f46892f989169cf059532f654930047829' 
  AND token = 'IcrECwxKJky8zSAf9rFk5NhX5mXZtR1dswIUYJTrYDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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