SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3afa1f57c26b2ba7d90c1c5b4a3cd8225a50109e6dc984eef6f050430eeb9adf' 
  AND token = 'XuhJ6VlFomBpPJF92Yg2Aj6nhbdpqqx4YWTQGWqSwgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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