SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'badf82a06e0469189aa34ca633369e6a7b63c504257d13fe85f9323bdbbc8da4' 
  AND token = 'SDRXXe763vrVlfGESAFHGK+NBXCvXYeY75WqMgYeeQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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