SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1205c9f7ea593c89eda1dc8ead7c2c3567c237df446023e62f652d0d98bbca05' 
  AND token = 'fT5vflNgpjTleQC5bbmsTI5MJvN+Ru0rJnAWsR8Fr5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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