SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a328276e3cce0f941c9aebc42408cc7de287917e2028fc2b049168b86e9307db' 
  AND token = 'KskXjV8VKsbJpBzzZzf6+IyCvlQDlOiOsXH1Z5Jjkm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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