SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94dcdc1d86365631a4d12772fb2753382f53624dcf9e2a5c4c3484783ec17e7c' 
  AND token = 'FUvB74qqnpGhCa+F9a5D1vw5lImWXAYnC5hikBJ3cY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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