SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc8fffa0f66a69da4cdd83a0bb71248eee16034c98049c17e2fadb21ce0cb3ea' 
  AND token = '5KnmLZNffYwdkpW1xhgiJ4eRXNlgzTvrnDefEk+Gx6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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