SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49461050a12a231711d0c8802cefade54d4813e8cbf2335fdb7a9d0aea6c337a' 
  AND token = '/kcQPq9HCBxIU+zWgRjzkX8f5EULI+eUFNMJhRlbDUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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