SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d11a33acde9805915fd924355da4a20a8486a2619f740abb5997a5ee5d1ed42' 
  AND token = 'NZaasbc541qHqaCniYf/99xgLlOyoeyVKg3kWZHBOUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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