SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bcc730b46e6d3aba9ada2ea45366394448b837e3eaad8cdaffe522d24a5dde8' 
  AND token = 'CPn6Zbz6cB5ulXOVEpaUpzSL088yuORIvW5Btu3+UkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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