SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '539cf6aa55bf990be813f3724700dfda69d48734e7a0485ec114931439aaa779' 
  AND token = '/rFWgmPdtG9aVaGTTg6X2BI46a1Gc4azGnJquk2Y/OI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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