SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d36bca89613b093b3a5d572d7a28875f3a7ed47cbda18f2342fd256a2df5b5b' 
  AND token = 'WFLkdbFsyFrLJ7UWqLYpGNbulEmgl+eBodwORdg/LXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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