SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2fd06506e26de0228a1ccc62785f7e2e1f33b26569d9900c71b84e90f11bbac4' 
  AND token = 'dxJkGJMAhz4lz5vLFVwFlUs7sk48cewHkbQJ+ccGdZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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