SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45492995eff630e9cf70fee9fea3dfd13609badf1afb0887cb1de0e9c7bab146' 
  AND token = 'Y2bR+IkeMbuKwXAP3nUmaoVay58CQYjDYdOYgqDS36s=' 
  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"
    }
  }
}