SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bede97a3d42667897532d4fc7d271487f0a3b2703866613e9566a19ce2acce2b' 
  AND token = 'h3u/k0E1zy8ZM9Zjhq60OE1lWwJ1ciaNpv/YUgsXFFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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