SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '618121ada6d32ef86d95138db9b9b5f81c9e3dd1f69cd81bad1e221c63b92282' 
  AND token = 'dnfodcpbuTxGzsKzpIE2mnTQZkgZf5M+SHsUd3lm9ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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