SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0bd9d5fb28e99930fb0ed526d4e3eb1516d4f353fb79a70d4405e84efa5c214' 
  AND token = 'Mz/Q5JghM0wIN+JHWwVh2XY0pTKot4gBd0W7l5RjcpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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