SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d99fab27a3c6630f27cd167e92bff253f737ccf53faea743e6be0f094cfd409' 
  AND token = 'rV/1wdUMqUuK7gjB+L0D7iztbBEdZ0xxWBYgsqpdPmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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