SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cd27b3256406bebc3f86942ccdc30457aaa5a2398b087d540c996cc69561c26' 
  AND token = 'o6iXFWV05Pn4A01keKJCDfhjOz/ID8KWrc3nWZxgn6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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