SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa152f6e173ee52a0b3adc656ce9df0a8579286af569cd10f3e464cb4aa10dd' 
  AND token = 'rS2hFgg+PXaFws5e7vtmpZgOA/EYE81YOoyqdEjW4zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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