SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0dfb417f7e61fd5eb3f379b379004469167d468b20369dc19c597806cda6d90' 
  AND token = 'mCqftbagZ0xhSNH7p9sr7IjpZrmfCd5tGyT4srmvpFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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