SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fcdaf75f49c49bdb6978056023d98f269b91b66786a264fdda287252ba43ba9' 
  AND token = 'N4MitBBzPB+ie5cgPQmR2b4yIDiZoyNIYouUFb9Acz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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