SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb7f93b6d54fb0301bdfb14ddc0fcfa46835289f2e5d725764a33c879a31d875' 
  AND token = 'FnFlL9rZgF4bSTJw6KrsoDL5sTkxyIqu3kiKPt+mQXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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