SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee3856476f88e10b4c41335af8ca5c5945178bdfd18d216b994d110f44aefa4c' 
  AND token = '2WM3sTDQK2/YfgYAgnBG09Z8VRLyinUBdrKSXBrh5Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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