SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5094e183cd6f5f397bee693046906302e5071e0f6695c2150d1f54af8ea3bb6' 
  AND token = '9h1EbguUwsYIZdnTK1tSGZmT8w38nh9qszAsmxy8IPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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