SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfda9c700f705b1b97d99c13eb784502236051b8b82ed0e74aac5b7f44976128' 
  AND token = 'f/xG87PXSzNZJCZsGdhbG+DI42xZiTwl96egZm33s1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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