SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28fd72642c50d8c881fa96dd2ae741625a058f4afc693181bdf9c8cb378a5bf6' 
  AND token = 'KaOrGx/XYbvKqc6jOrQDnnI+aER8QNVEnBG5hPp9ZTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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