SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a26f38d849e15832dfba33659682ac49b9ba6b7ba8024e74159a8326cc9a6c' 
  AND token = 'cjm6QY9dvc+GkEhKAzJ6qGvjY/dniw14/smTnbu2mnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}