SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b81d9163996bd47cb143381953c37262d343c0579ff30b830b68667828e12268' 
  AND token = 'KoZipB535aLKA++Ntx80GxUbPl8pobjBAkLy3YWlYVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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