SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '79c8b3f52fc90f1a212aa592c65041216224cf1eceff87776fc0df8bc8a4da0d' 
  AND token = 'YOQikCZa2cv+NrU9p+bBYYucw54lqF1oyz/H53rrGw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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