SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bec16e40021821d2696eed934dcb256dffce0fced9f76f5af3de66166686663' 
  AND token = 'XAQEvU0Ic9FSNOOXCLmPN4c2afSiTQjQPqwFHtKAiic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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