SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e15a926805d741b66023d164d72c472563133eb6da314ad03a5dedab9ef70b4' 
  AND token = 'MRIsw+bxBPQSM36QLrANIUxKRSLKdVVlbMmvYUQ4O3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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