SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8099b5a753bc91bf327656fd84a5e75ce82111f5a16a15ba01d5d9c2b7a99a3' 
  AND token = 'xp+QijpQLV3mz3wCBlI9TTY+vBaetHq13oxHJmysXic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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