SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83c6cf339bc17c20713f9e54f4a94f3a36788af51dd24789c34c35d6b4a09406' 
  AND token = 'pAHWs2gnLfTzsQct5bPKYJPREbpG+bNtVxiGA4wYx6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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