SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b9faefacb764b6992037a4101f4c9d89b3b349ec251d49710f4bd1a0a172dcf' 
  AND token = 'f3wrnSuJsbqKG0goFE+eajFzCpM0brUbHenFzmTH514=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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