SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eca4d0d2ddb1b59ffb86fb46af987a7a11c10a2ecda42c041382954a87b3eb2' 
  AND token = 'sJBqLPVuXokfC1yZKlCdO8IIcTbK3KPnrO6jPnWVDzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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