SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6676f91090fa5f9d8899dd68e5e39d35e88bb94afd3d081b7b31db689e742ee' 
  AND token = 'lq1i8b5iK7eGovPxOfkSgBHlZREMqyINOYH/LaN56MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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