SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5621c299b187e800ae1b6aeeeea0d23269e7f149ee492501cfd6f01939eb5d3' 
  AND token = 'PsjMwef35wjD/1oNDx6jx/pP2dphV8GPpWIY9iawgCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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