SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b988a3ca1d1e091bb0bfcb36ac88109264f84c1254e9ce017d3bf8a1a96fa3' 
  AND token = 'SUbsTkDz6zrY9KoMZnYvO57ayIqed8711cn9LbWMW68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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