SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3be1e9cdb1cf94ebad5aae21f188c8d9a24bee7ff6fd130d52950a8503013e82' 
  AND token = 'FLziDMKksy4X/xNAENLfydqEOjVqOpqsQRn2GatNkLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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