SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7e85b6b4c309213cac3837bd0f9feb7afa3648c3f52b751160f86714f4a914d' 
  AND token = 'FIiF8okzYDKvOXZ9PhzfVTZN+DyKSxlC+E88+YBpfcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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