SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81cf360dc86233adbe72a727c9f54bc645b63b835741d3e255a3fb17e5aad69b' 
  AND token = 'W71kptgkVB/upx1h/KhJHWRMRYq/YIC4JJBzzhQdOPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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