SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f1adee396775aeb31587797a16bb560e4b8d814148c958a1246e2a009077620' 
  AND token = 'RduXraTBasg9Uo2PVSTgnuUfAd6NmuHDDyuxSyzuCGk=' 
  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"
    }
  }
}