SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888dbc700561dcf95cc153baa4686bbdf62f2fe3aa3d9884b2ac8556b4a3f539' 
  AND token = '0V+h6UAmGAJBproOM1dKpquRbSISBgZRHEFWBL45/cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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