SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b20fbee0a48ddfc303057d9c3cbc1733a763249c1d668cf08d87d57eff2414' 
  AND token = '/7f8bGhXUAnqjrpE6i1+itFsjifrtc9mKuhs3nxf5nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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