SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a61633430203cc47fe120e844e5067b55a426a66a71d57dec3dc959dd8cb882' 
  AND token = 'KT7+hfYjQ0F8c6GKynWhP0rpH3h9/M6GSlvAPdDIvW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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