SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4518ac78e15f7aee55a704d8e960ebdb1831d85cbece430585e5302567457c0' 
  AND token = 'gsLls12egG/rUzXwp9gIXAEOwtFerGl9MFhjAqFS7WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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