SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8deeca5710dd2d745bf2f9e6d49ccf3705957fda223974c6a9a3d3c3e31a2ae6' 
  AND token = 'c6VOqw0SJ2kkiZ4egObrSxJI4FuwpCsbpyIxHtchK9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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