SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4943c1383e66eccac103a488d56efeb709d84fda1bc86a976862153bd013dfcd' 
  AND token = 'NKUe+oq3glSmjUDVdg4r5hCUyWWAAvcztIraQAhnH6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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