SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '620a9256cdc05b891b223b600fcb5d26a9ddf258625894eb0027cf4dda7b6220' 
  AND token = 'LZWuwp7xo49nzzjzKhZHZXJ5Vk5Zl9ZeHPU7rvWWrwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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