SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be7c50dc310b268c411159e74bb4ff4dfe7e0a5ef1b4e92fddef5c880c6d5dd2' 
  AND token = 'qAZKqcomcGgd87khEB2O7nP59ZSVzcSnaA7lq9FYsxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}