SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d217a5b38b58a31d332f1f17ef2ae37a53eace2ceb50c5c95d2a92aab041d0' 
  AND token = '81IvD/nu+Kp8qcAVtL13zDB5UULZvKvcHuAkGxsUyPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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