SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40601fb8b11fdf61f6e399127e8ed929f9e409581daf4ee3f1a7f656aa52ad39' 
  AND token = 'UHfano7WtV5YeHoJyz3fo3T4cT3UTSuTZWUnhZ5e3VI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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