SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88eb40db8d60551a78a3e11207367eda20aa8b3451782ce569897d567fde0537' 
  AND token = 'jJ8GI9AuamgfMnAcJXwwoaDS8WQOfZZUnmbvqfwgq/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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