SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854233fe7e9f7d8f36d28680c2f184375cd0b64e40892a394d67ec789d2b9338' 
  AND token = 'fpAKpjhb6voQ4VtvNEJQvJCd9pDVjqxQLKglZ4GOYOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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