SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb18c2796a5e80c85b70964419874c6210089d83ffd95441110499c317ee3f4f' 
  AND token = 'v93W9u3vkexGzVLfcXE+0F2RSSQH9HCkpzLNftFASHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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