SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba54d7f51b8ca5eebfdfb309f53d0a4e44c4c1be3f43cc240ee1bd22dee385c8' 
  AND token = 'cxue+PMtyx4Xt5j7ucsWzu47SbbpELxqGor0jrVHWN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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