SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61cd872fff6b34284d89a9e66246096d1b0aa269cb4760283c735712daae993e' 
  AND token = 'm8GhP9dzLtLZyrhQ+F90b/uFN5SjVK9hEjcg3q5Tvcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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