SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93a08faa2591024d705ae16b88d1d6df715721771b1fcfdb844df511ebd126ab' 
  AND token = '+pgRyfGINenYRvKJDK3pkqI7fsPZJUjrVhN+SrQn+YA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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