SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd239cddeae3709e130ef60b7cfd9a96ae39466e3d8b362c7364774d989d75469' 
  AND token = 'yBOjmJFftSZJg7P+mUu97uXsLfqKdLOqNQ+NheBDIlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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