SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd6f9aeb5002ff91bb27249e2bc8414d0f0528c40a0acd45f719f712095d922a' 
  AND token = 'Bl+U9cyLKJy5XpX0KgszWiccBxLujsAxvqunnMRelJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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