SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b047528f39474118933756ab22e7a4bbf7ae04fb667cdc170cc0cbab81feb4' 
  AND token = 'QMwZ1kqzGZsSAzZy/pLrLUnDVmTdGwBJE4pHQPBXZ1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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