SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438af356226f7733145befa37823f19b751063faab80fe47ad41cdd37afc25eb' 
  AND token = 'nF84+tNKJCwpSIZrot8tRnvh/UUBHgqMLEDV2ivMXLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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