SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead04f8b2fe1774263ae7f3a324f1ee9274050d56a650b4821def3c93ac485e0' 
  AND token = 'RR7hA5VJTw7037nmBoUpvUfuyRkzlyUiaj2mnydxmAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}