SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c518a5d83909befa19c7a41c5ffe6680e21c0b518d4db76f21280e7d406a6ea' 
  AND token = '3dILBJxpEOWvPcXuOFXqKYtOlLIHZNjv77DV5H+0Hjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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