SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '85e9969a92e5b6ccae063813abc7e62801d72b414565b4fdbaf297fd7bf81f52' 
  AND token = 'N/XVL5YnOme0wTLeh4ZzUvH1bNzIIebDVvX//guTbzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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