SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc71a2c5f4396f6d07897f8d22e4f755b1b95ac8cc1b5de13562cba2aea26bf' 
  AND token = 'OSqUsAhquqhirQADm+xEYAky1DnZNvsJ3sLWV038QGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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