SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '31988035b76547225db06608f1eeccc6b48441a9f876ad95ee810718e7198b07' 
  AND token = 'fIVpFTLqJYbo0HaRHxe4/2s/ooao2RAjzIibnIs86Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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