SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b31bd3aa78cb48d3ea71dd6c32531d145d91affbe0676b4c6d790c57c3d1182' 
  AND token = '6BfydR5xL/DzWuzLUkmvto/Vlew9xX4bG/CpOJEKcSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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