SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d6ce1f1aaa827182b9dfdf56a147ed404491d3105920bab9e4da840ed19dcd9' 
  AND token = '3jNsgsdRZeBOw+Ec/DWAX2qLjaUTIJo8K8bshvzE3QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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