SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a128854c83553fe64d27e72bd91b8d3ef37066fdf537a83d843d7290aa21851' 
  AND token = 'ISxa/RH3P3Mcjwzaaz9EtsNQ9Vk+RjByz2P9oKQ3wh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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