SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dd859921d5650368642a75fdceac852290365f6c1c7f8175fb93dba4b0f5a0a' 
  AND token = 't27Ejt6OTWJB3k+49W2LbIWhn7AhgZQyG5aM42fWQGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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