SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d7ab2e48125dde958b238726630b967ac67e2d44e9ddcaf3cbfb17423ee4da' 
  AND token = 'kEGItlgPQbzBqEIeRnkug2zNH8CrR3z9NXaUXw1tpJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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