SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4d26c8bcb9a405ee9712fa92b08d223567264b44e98e82e60bc13b5bcba9be82' 
  AND token = 'mCNDeB/SZ/9Ng6qLdK3iKV3E4Mw4tbu+0nFjjbQfgEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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