SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c3eb1f2f19e44ccf7f23cb4ad2d00b96d0d9dfc50b957e0ca61e4cafb634f64' 
  AND token = 'gSsmicAdsAuQJKi75llopttjvQRUGTYr68k78enwtoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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