SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ccadd75ebe1d93401ad5596177dc96955a61b3f1b78480e45d36af9f9fc44b1' 
  AND token = 'j4MqK77aBUzNayrCRTCj0YEoxWPZZVyqapKM+Ic16hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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