SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97a3064e17796a192c0ce557538c10b026faa9a43a0c53c701a303c1211f1286' 
  AND token = 'MPTJovDCoqtfDPEWvbVfLfuCZ0qSD2/HV1NEIMXsvO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00098

JSON explain

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