SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c8df4f1718941c48c663174a46f5828da78e8fb27a45e915bdff563eb5119f' 
  AND token = 'Da+n5+uAkmxBI40MXuoP2vx1v0hvxrzYbmsvlCgVqZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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