SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cafdf4d7d44e7b96ddd6ba84da71a6cc7d0b39b89da94a9408af6492ac50a2d' 
  AND token = 'zvBP4OGJFNleWzkK7EpLj5LzeT6qCWsAc8xA8DuRfcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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