SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85105ee68ec74f78b34aee2b217d0b96501f31ec00e09707fe1a2096c406ca35' 
  AND token = '5kvE1VJBgOvBtuSWjrsRSkt5+BsMXhPRJ6OG+Fj5xTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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