SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248360f8ae3361e01b49608dcab1afd5518ef943ec2cbf0ed4d064035efca309' 
  AND token = 'BvJrjBtrhDJSZ69J0pmbFjuzuifupJRVbxgCGgM83Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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