SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afbb97a01774e27510181bc9a25500029519cb4c82f242a4200bb0d96f941376' 
  AND token = 'TmEpaqKPkDnKw50fidCq97UN3j/PBvzBNR1WIaGf+uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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