SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '311709b711b46a29a4747e897effc47a332ebc9b7b21be233eb00a436308f624' 
  AND token = 'vWu/74DydGL5aVtIJtCuAxUzGsJDo7IKET1fkZowB/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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