SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b8b98db13183c92a79a8286d0242df667f5eb66254c1fbba9b4af5da3eb8ae5' 
  AND token = 'xDKZ2QpOMCxQJy5g5nrpWnZBbkf0tA4cexjvs290kAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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