SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e703a6fe1ebe9119b2ecae0dcce7fd24134f9d20bc7447749adfaca388293f' 
  AND token = 'jH1Q3zBZGKYKVgDHRLjXhGd5bgDbmfwdhK8bqraIYr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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