SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbb8294b176c8fc15f98cedabdb0934df68fbeb3fc36132985a11cb6ee30d38f' 
  AND token = '0qqq8kDV5l3TpxDyzP6ZBZxpHhf4lQZPdZ9r46AttBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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