SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '221633787b0517dd0d7a20a193cbc0d8930fa3f76ff882e21cb7f0f948f19772' 
  AND token = 'fEX4f9LJzDngmEUwpGtiFSuXYpfOkhgzBYlKs4r5SIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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