SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af6ad3fe8178288af8ceb600af6a401572e6ae92aa6775af63d85f2a32a459c0' 
  AND token = 'SxQorkXjwSmAJCWvR0k8g41LNywKiuMzY0wdT9JY6K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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