SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe31c27c72e62398746cc7007cae8e2913a8942946227f47a64909f986861ae' 
  AND token = 'fJe4Ublzf2EDw2eJNn0K48qH4Oru9JFiPPxfdQQbnTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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