SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd59a71d5940886a2e9d40f42fe4a336b74f2a042c813bf6759761e4a34a9217' 
  AND token = 'pRpL7hJCc//BqsFzmzB9FLaS5zZAO/Ka/FQolMLutRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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