SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cc5a47617fdb5f79786d7aecb5689b95b65b9c4562780d4960f160a0c17d60b' 
  AND token = 'kZ7V6WIaj3XuCWI1dbPJ8+nmrF1YRqjqaUqu8N1KvEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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