SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8f6491f9567096848abe4fca6511b42dfa2b9c652a86aba44bca72fc6cb7f6c' 
  AND token = 'rdjRB6EppORAZJXC9wkg9KvsNYUZd2ErSJxOlaPWaPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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