SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ef17d00848be7b9187979827498ac67c2821216bcdb6764bec3c2f6d97b678e' 
  AND token = 'FL+wOg2Jtyfs73QN6faOQQhxJ5IEwpYWU7xpUxSn0ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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