SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aecdda244679ab82c8f3101f140794ef791afc36d09e6baae079229357bb3811' 
  AND token = 'SmzCGp9tWEytidOlo/vDQq1WcfTHsGSpMtseFniUXvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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