SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f26a991a813b664c1e41dc0bd81992acd80277d31048ebb70bd9e4c290c2019' 
  AND token = 'a320jVCsLB8RsB8kvQPa4BfsplfVZoOZan4EUkbaGVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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