SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef9ba07134f6fda7651ac15a55d1b31421218eca395d868e99d5203348c0b0c' 
  AND token = 'wp5h+vBw5SdlNHXiElnuUS8zZ0jw8UmKvV7x7Dz9Xjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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