SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a09dd94faec4d15d13234d0cbf08effeae8d043d58d50c71752691a0714ff6d9' 
  AND token = 'IdG/yZij7rpU1eigQ2+TAindWkEb9qqr+zOTkRD7zkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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