SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ced4a1b4d2f86c98ccdbdcc33c1441b5097592aa6cb99ed6178de8fb97a45c0' 
  AND token = 'KvrvqXNY2eaeAOFmDk+x50WIkv5LY/gsnh0lpdnuYTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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