SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa316b8e6537084783520f14cac93e5ae9a04a6fe4c171098e72c6e038519956' 
  AND token = 'RStW6eY66KWiCS0xtMmXPbZ0sgaCkNbTHdZ8z1sDBuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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