SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '617e67de2770f01684aa3bb32e2573d46be8d2bffe132c90782171163d513aab' 
  AND token = '+9TgRUh56JPVR/KzWpqhZnHqxp+hjt2bK2ss44Oaov4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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