SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eda73bdd2464b1fc6f8b51d015bace5010ace4377304ebed749ad348d1258b6' 
  AND token = 'yTajDtBBgqtOreps8j/+vydBsPVLGG6VPBZJ8C5UgSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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