SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a3efdc92a1091f8704628fa539def141f85140efe786ecad0af0a08c8748739' 
  AND token = 'K6kxssFBkd3Q3Ma0P3T0URQ3BOlzArnfOrEPkDQmjaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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