SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2691a262ad14c9c4be1643cf57bfd3c2ddff289064a01b7de5f5a574266dc1a1' 
  AND token = 'FhTzOgtIufLlAg/H1mCvRHsWo1HJhnS5pl9Qv4zL7Ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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