SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bae0d763217f99a679a2752c5234dd1daf2f6eb0ed7fc61551b5ad022fc1dd3' 
  AND token = '6jBl6TZhwzD26CWHkmYWpijpyr01RDeE/KwaObeUZTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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