SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a166e01fb9fc832f0e88d628525a01deb9619fab657f310ce4d28d33b5b37914' 
  AND token = 'yn9eY3qgFGWiRI1lbPpH7cy2anVLEl8wj0BrhOMV/IU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}