SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebaeb9fa2b48e66751fe872ab28893c0470013c3cd5c3095041c5d7902547211' 
  AND token = 'VZhMrh5l7wSgEHxwTDzHs9rm+IS8ojWrU/k3jjWQi+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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