SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5086d513943cf2a4a43b52303efa4b7de334bac91e81c6d7fd47dbdf1557af9c' 
  AND token = 'sFOCME7zduXbaR3zJ3xqA+qW5llLah+UqPXLehMwPSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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