SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3dee4c5af3def6cb8f0028f3c492893f8b2a70280d5aa887a59cb653a10d143' 
  AND token = 'D7M4ue3VbZBq9IANqXUv2PO5flKOLrXZgHqoFAJtyC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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