SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ad313e8cbb1e5019ec19c079f347214a6e1ddcb58c524b283ec56d8f9624227' 
  AND token = 'IAVIjCcn2esbHpeqdNTobtPreNzFRfkYkcMySDBBFRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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