SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca891ce5a15b2f7b3d5bf72504fb16e9c4d8bde4c31b0732b4fdaf9a91637644' 
  AND token = 'fSopj5zM35612PVT1qXiHrYMyD1Xrd51IZBXa8p/0rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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