SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6720302c54a7c837563f4fb6df7088603c39b4c0989d190ccda1a6b5d336b1ae' 
  AND token = 'qRUCJjLXN+LIWB9huEwrwJ0Cq3GILroUECusL1KWHK0=' 
  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"
    }
  }
}