SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c726d0d982f324fc4a738aecfdb911636ece76149d98b4dae86b8b08622769d0' 
  AND token = 'yZhPr5MqJowoyWGVxLfOF8QgVCmoLOeQ81xPF1799Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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