SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e538f993bb066d572c2a97f7f7f6eab9ed4458ad9b235f0ff104fd5fe41b6334' 
  AND token = 'pDwSmNAnqSkKaZr2dqgPBt4MvN19iJiGxifSAGzWMB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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