SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8be010533523abbedc3294108559287eca4dd1adcfaf164228b9d8ce62f7b0d8' 
  AND token = 'Z86zZbgT0+AcaSvGBBPu2//bBsMXIUKICTLru+Wkpkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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