SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd82c96be87bb885d1653c117bb96e694f3570083f34383e48af7536089439af4' 
  AND token = 'c6SiNCBs5prS82FFiVJfsbywlNCZuSar0p3azhJm7k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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