SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec577059569e1f1045eb9923cedf9d7b486e38028e86366a8bc350e137cbda1a' 
  AND token = 'czkOXHy4qs526FSfSaecHKm4l15nyo6sq0bBPVCwS5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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