SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f7198a443daec9a1402431eb0722d0ac4ed5a5d961cbf2a7410ff623fe3b76' 
  AND token = 'xsYVcKmeAch6VuWzEET2NuLtc3RpkYGR+vl6qIwbetU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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