SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a31ce0a9dfabedb885a3967a4a0ec3d49075b04a6a97ef2899d67195411fe66a' 
  AND token = 'jCuLTcg0vO+FrPZLQ5ADK77Pei7UQfgyJtMQwZiz47o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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