SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39498a919ecb84df9d632f46aa8d2c43888e90c71ef00e49c289bed0bf8cfb38' 
  AND token = 'wgaSWN3pZMZOocikEaxXi0heGKurtgZaYb9PDU4sD4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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