SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8073fdd8ae0c7388eab65a55af2f225379a323668f996dc86fd48979039c41dc' 
  AND token = '4pvA529U4aKzw7qyhbYs0LGB+suQSvSdIY9r5CnIcGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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