SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dda86974748dd6e243d6dabc30d728f8eadba9db12dcf32f5632860bbf19a14' 
  AND token = 'iwcM9TElX9WnSRr8Id/nvYT34trMqXezFPwHVfN7jJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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