Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683e3d619478d5bd48b23c831940e8f20397370a59f9fc7192ec261add090df7' 
  AND token = '2mz9wA6e4ys7XsCc6LVHziODGeMKZuDyGUQnrgsnXco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}