SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c08b9b639d90858ec75a05bd2e88f55d854e2b2b83306631aae395e01fd43c64' 
  AND token = '1TgZvfiellNiozyKdIBqV7LEiLwVyMUZRuBtFrx1eS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}