SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e06164406314f7ecd7591e89cccf6093614d97f21455321247718cf36a66473' 
  AND token = 'SeuV1yISPaBQbmCMCqgq4tfWWHjGH9kzQHJzNUM0JyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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