SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '209c80bdd588521ffe2db7b7c405a447d474ccb57b34b80741c6cab99faac850' 
  AND token = 'Qvcfjb8CwUTsOqkcphtWOQp3eRd04k16FxSlW5dvSms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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