SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f98fedfb3633188d1e5fa77023ec078f6ae696cdcb21114328ddd0516ebc35b' 
  AND token = '9aeHZsreCbMVJqIqeABwQhz2oKM+bcVGEgbNy5uY8gU=' 
  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"
    }
  }
}