SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e2584304cecac37a01b5c4878b5536c06fb8b05dddd76b5acec8385b628a18f' 
  AND token = 'Scc5s20WJxPJ2SKI6QVwv0XjEjs6WKlsVk+wuU0DbAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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