SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '17c090f41a7a95680da13d0f65c4e8b1ec3216602482b285f33ce69fc9c3f82c' 
  AND token = 'ZTYzTkvrsnZwVNg9NlRAcSg9nSnlTot2Tz08LEWghFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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