SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9abaadb529fe16e9dd1deafe09cade11dad72978a4d2c91975d323def7658bc' 
  AND token = 'qwYXCc2Emaae0oa88oNslYuYrTtLMZg+6FZ5KsY4WPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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