SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd030a9a2fd7690152e9ddcb841ddc38c0ed2ce6e87a0f83a966fe97bb7979ae2' 
  AND token = 'SkJ5RXDkn7syTJ5mAo2CFzQTE9wt2hdUt+YBrnKGetU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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