SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4006a77e8a32b5ab92e51b56a81a44bd83c53300e55609a437b450ae25e00d80' 
  AND token = 'h6n9SwvpvTy20dLE7y1jGDIvmzRFjCzr8KHztcWrnpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}