SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f763fd2fe547ee51027edfa000cd268c5c41c5439f8a4e3405e3934806af119e' 
  AND token = 'vxJSJTVpP7mh2sWbYlAjSrxZMNuPto73x9ywn3qgP/w=' 
  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"
    }
  }
}