SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27546a448b711448b9d731e9c3fe92f94f383b0da3de9ddbf3f6699562b71986' 
  AND token = 'bWGJu7HDpZeNd3MdDDVITotl5IMdaPDJgidjcShdrzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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