SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bbe469b812ca18720b0fe9121b44fa2841268b9a3daddb26420e1ab47e22de8' 
  AND token = '/vgJwwEj8NnXhMktDjKguikSxSDl8OCY6B1ZmJCww8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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